Laminated bus bar for use with a power conversion configuration

ABSTRACT

An apparatus for linking together power switching devices having intra-converter connection terminals to form a power conversion assembly, the apparatus comprising a planar bus bar including positive and negative DC bus layers and insulating layers that insulate each of the DC bus layers, the bar also including at least a first external insulating layer that forms a first external surface of the bar, the bar also forming at least first and second linking edges and first and second pluralities of linkages formed along the first and second linking edges, respectively, each linkage linked to one of the positive and negative DC bus layers and configured to be linkable to at least one of the power switching device intra-converter connection terminals, in some cases positive and negative DC bus linkages are also provided to render the conversion assembly extremely versatile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/260,064 which was filed on Sep. 27, 2002, abandoned andwhich is titled “Compact Liquid Converter Assembly”, is acontinuation-in-part of U.S. patent application Ser. No. 10/260,783which was filed on Sep. 27, 2002 now U.S. Pat. No. 6,721,181, and whichis titled “Elongated Heat Sink For Use In Converter Assemblies” and is acontinuation-in-part of U.S. patent application Ser. No. 10/260,056which was filed on Sep. 27, 2002 and which is titled “Compact LiquidCooled Heat Sink”.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The field of the invention is power converters and more specificallyconverter configurations including heat sinks that reduce the overallspace required to accommodate the configurations.

It is well known that variable speed drives of the type used to controlindustrial electric motors include numerous electronic components. Amongthe various electronic components used in typical variable-speed drives,all generate heat to a varying degree during operation. Typically,high-power switching devices such as IGBTs, diodes, SCRs and the like aswell as storage devices such as capacitors are responsible forgenerating most of the heat in a variable-speed drive. It is for thisreason, therefore, that most variable-speed drives include a heatsink(s) upon which the power switching devices are mounted. The heatsink(s) conducts potentially damaging heat from assembly components.

Selecting the size and design of a heat sink for a particular variablespeed drive is somewhat of a challenge. First, a designer must be awareof the overall characteristics of the motor and drive pair. Second, thedesigner must understand the industrial application in which the motorand drive pair will be used, including the continuous and peak demandsthat will likely be placed on the motor and drive by the load. Third,the designer must accommodate, in the design, certain unexpectedconditions that would deleteriously affect the heat transfer capabilityof the heat sink such as unexpectedly high ambient temperatures,physical damage to the heat sink such as mechanical damage, or a buildup of a debris layer, as examples. Fourth, the heat sink(s) must bephysically dimensioned so as to fit into the space allotted per customerrequirements, cabinet or enclosure size, or the like.

In the past, air-cooled heat conducting plates were used to transferthermal energy from electronic parts to the ambient air. These werepassive heat-transfer devices and were generally formed of alight-weight aluminum extrusion including a set of fins. As a generalrule, heat transfer effectiveness is based on the temperaturedifferential between the power devices and the ambient air temperature.Of course, in order to provide adequate heat conduction, heat sinks ofthis type oftentimes are necessarily large and, therefore, bulky andexpensive. If high ambient conditions exist, the heat sink becomesineffective or useless as heat removal cannot be accomplished regardlessof the size of the heat sink. If the variable speed drive was in anenclosed space the heat removed from the drive would need to beexhausted or conditioned for recirculation.

By forcing air over fins defined on the heat-conducting plate (e.g., analuminum extrusion), improved cooling efficiency can be realized. Largeblower motors are often used for this purpose. However, as the finsdefined in the aluminum extrusions become dirty or corroded during use,the heat sinks become less effective or useless altogether. Blowermotors cannot be used in environments where air cleanliness would clogfiltration. Therefore, air conditioning equipment is often added tointernally circulate and cool the air that is passed over the heat sinkfins.

Liquid cooled heat sinks or cold plates have also been used for someapplications but with limited success. Generally, a liquid cooled heatsink includes a series of chambers or channels that are formedinternally within a sink body member that is formed of material (e.g.,copper or aluminum) that readily conducts heat. The body member includesat least one mounting surface for receiving heat generating devices. Thechannels are typically configured so that at least one channel sectionis formed adjacent each surface segment to which a heat generatingdevice is mounted—typical channel configurations are serpentine. Acoolant liquid is pumped through the channels from one or more inletports to one or more outlet ports to cool the sink member and henceconduct heat away form the heat generating devices.

The industry has developed several ways in which to manufacture liquidcooled heat sinks and, each of the different ways to manufacture hasdifferent costs associated therewith. For instance, a liquid cooled sinkcan be constructed by forming a desired serpentine copper conduit pathfor liquid flow, placing the serpentine conduit construct within a sinkmold, pouring molten liquid aluminum into the mold and allowing themolten aluminum to cool. While this manufacturing process has been usedsuccessfully, liquid molding processes are very difficult to control andthe incidences of imperfect and or non-functioning product have beenrelatively high.

One other sink manufacturing process that has proven useful includescutting a at least one channel out of a sink body member, hermeticallysealing (e.g., vacuum brazing) a cover member to the body member tocover the channel and then forming an inlet and an outlet that open intoopposite ends of the channel. This two part sealing process is much lessexpensive than the conduit-molten process described above.

When designing any liquid cooled heat sink several factors have to beconsidered including heat dissipating effectiveness, volume required toaccommodate a resulting converter, and cost. With respect to heatdissipation, in the case of a power conversion assembly, there aretypically several different heat generating devices that are similarlyconstructed and that operate in a similar fashion to convert power. Forinstance, as well known in the controls arts, an AC to DC rectifiertypically includes a plurality of power switching devices that arearranged to form a bridge assembly. In the case of a three phase supplyand load, the bridge assembly includes three phases, a separateswitching phase for each of the three supply and load phases. Here, anexemplary phase may include first and second power switching deviceslinked at a common node to an associated supply line where the otherterminals of the first and second switches are linked to positive andnegative DC busses, respectively. A controller is configured to controlall of the three phases of the bridge together to convert the threephase AC supply voltage to a DC potential across the positive andnegative DC busses.

In a similar fashion, a three phase inverter assembly typically includesthree separate phases that link positive and negative DC busses to threeload supply lines. In the case of an inverter, each phase typicallyincludes first and second power switching devices that are linked inseries between the positive and negative DC busses with the common nodebetween the first and second inverter switches linked to an associatedphase of the load. Where the supply and load voltages are large, somerectifier/inverter converter assemblies may include several three phasebridges linked together thereby reducing the load handling of eachswitching device.

In the case of a rectifier-inverter conversion assembly, a drive circuitis provided that controls all of the switching devices together tocreate desired three phase output voltages to drive a load linkedthereto. In this case, it is imperative that the switching devicesoperate in characteristic and substantially similar ways to simplifywhat is, by its very nature, an already complex switching scheme. Forthis reason, converter designers typically select switching deviceshaving generally known operating characteristics (i.e., that operatewithin a range) to configure their conversion assemblies.

Nevertheless, as also well known, most switching devices have operatingcharacteristics that are, at least in part, affected by the environmentsin which the devices operate. Specifically, for the purposes of thepresent invention, it should be appreciated that switching deviceoperating characteristics change as a function of temperature. Forinstance, an internal switch resistance has been known to change as afunction of temperature which in turn affects the voltage drop acrossthe switch. While each voltage drop change that occurs may seeminsignificant, because rectifier and inverter switches are typicallyturned on and off very rapidly, the affect of changing device drop hasbeen shown to be appreciable.

The problems associated with voltage drop variance are compounded wheresimilar switching devices are operated at different temperatures and isespecially acute where control schemes operate to simultaneously controlall three conversion assembly phases together to generate load voltages.Thus, for instance, where one switching device is several degrees hotterthan another switching device, the result may be unbalanced phasevoltages and hence imperfect load control (e.g., non-smooth motorrotation) which increases overall system wear and can cause systemdamage over time.

For this reason, one challenge when designing a heat sink for use with aconverter assembly has been to provide essentially identical heatdissipating capacity to each converter switching device so that devicetemperatures are essentially identical during system operation. Theproblem here is that coolant temperature rises as the coolant absorbsheat along its path through a sink member so that power switchingdevices relatively near an inlet port along a serpentine coolant pathare cooled to a greater degree than switching devices down stream fromthe inlet port. One solution that reduces the heat dissipating capacitydifferential between similar switching devices has been to provide aheat sink where the spacing between a cooling liquid inlet and each ofthe sink surfaces to which switching devices are mounted is similar. Forinstance, where a configuration includes twenty four power switchingdevices, instead of mounting the switching devices to the sink in apattern that tracks a single serpentine cooling conduit path, theswitching devices may be mounted on sink member mounting surface to formsix rows of four switching devices each where each of the six rows isfed by a separate one of six liquid coolant inlet ports—here a manifoldmay serve each of the six inlet ports (see generally FIG. 23 in U.S.Pat. No. 6,031,751 (hereinafter “the '751 patent”) entitled “SmallVolume Heat Sink/Electronic Assembly” which issued on Feb. 29, 2000 andwhich is incorporated herein by reference). Thus, in this case, coolantfrom each of the six inlet ports passes by four separate heat generatingdevices and device cooling will be relatively more uniform. Thissolution to reduce the device temperature differential will be referredto hereinafter as a matrix spacing solution.

One other solution that reduces the heat dissipating capacitydifferential between switching devices mounted to a sink member has beento provide a serpentine path that passes by each heat generating devicemore than once so that the overall cooling affect of devices is similar.For instance, assume twelve switching devices are mounted to a sinkmember mounting surface to form two rows of six devices each and that asingle serpentine path is configured to include a first linear run thatpasses adjacent the first row of devices, a first 180 degree turn, asecond linear run that passes adjacent the second row of devices, asecond 180 degree turn, a third linear run that again passes adjacentthe second row of devices, a third 180 degree turn and a fourth linearrun that passes a second time by the first row of devices to an outlet.

Here, in theory, the first linear run should include the coolestcoolant, the second linear run should include the second coolest coolantand so on so that the coolant temperatures through the first and fourthlinear runs (i.e., adjacent the devices in the first row) should averageand the coolant temperatures though the second and third linear runs(i.e., adjacent the devices in the second row) should also average andthe two average temperatures should be similar (see generally FIG. 2 inthe '751 patent). This solution to reduce the device temperaturedifferential will be referred to hereinafter as an averaging solution.

While the averaging solution and the matrix spacing solution work intheory, in reality, each of these solutions have had some problemsregarding temperature differential. With respect to the matrix spacingsolution, in the example above, the fourth device along each of the sixseparate coolant paths is warmer than the first device along the samepath as liquid passing by the first three devices along the path heatsup when heat is absorbed along the path. Thus, while better than sinksthat align devices along a single serpentine cooling conduit path, thematrix solution still results in a temperature differential.

With respect to the averaging solution, it has been determined that,despite multi-pass designs, at least some temperature differential stillexists between devices spaced at different locations along the coolantconduit path. In addition, in some cases, cooling capacity may vary overthe heat dissipating surface of each heat generating device. Thisintra-device dissipating differential may occur as a multi pass pathnecessarily requires that the coolest pass (i.e., the first pass by adevice) be positioned along one side of a dissipating surface so thatanother one or more passes that include relatively warmer coolant can bepositioned along the other side of the dissipating surface.

With respect to volume (i.e., the second factor above to consider whendesigning a heat sink), as with most electronics designs, all otherthings being equal, smaller is typically considered better. Thus, someprior converter configurations have provided sink members that eitherfacilitate stacking of relatively short devices adjacent elongateddevices (see FIG. 19 in the '751 patent) or, in the alternative,alignment of similar dimensions of different devices (see FIG. 13 in the'751 patent).

For instance, the '751 patent recognizes that, in addition to powerswitching devices, converter configuration capacitors also oftengenerate excessive heat that should be dissipated to ensure properoperation. The '751 patent also recognizes that capacitors typicallyhave a length dimension perpendicular to their heat dissipating surfacethat is much longer than the thickness dimensions of typical switchingdevices perpendicular to the device dissipating surfaces and that theswitching devices typically have a length dimension that is similar tothe capacitor length dimension. In this case, in one embodiment, the'751 patent recognizes that overall converter configuration size can bereduced by providing an L shaped sink member having two legs that form a90° angle, mounting the capacitors to an inside surface of one of thelegs and within the space defined by the two leg members and mountingthe switching devices to the outside surface of the other of the legmembers thereby aligning the similar capacitor and device lengthdimensions.

With respect to cost, unfortunately, where an L shaped heat sink memberor, for that matter, where a sink member having sections that residealong other than a single plane is required to stack or align capacitorswith switching devices, the relatively inexpensive two part sealingprocess described above becomes much more difficult to use. This isbecause the two part sealing process generally includes vacuum sealing aflat cover member over a channel forming body member. When the channelmust reside in more than one plane and requires a more complex covermember, tolerances required to provide a suitable cover member would beextremely difficult to meet and the sealing process would be difficultto perform effectively.

Thus, where the sink member must reside in two or more planes tofacilitate stacking and/or aligning, the more expensive molten-conduitprocess would likely be employed where the conduit is formed into thedesired channel shape and molten aluminum or the like is poured into amold there around. For this reason prior stacking and aligningconfigurations have proven to be relatively expensive to manufacture andoften are not suitable given cost constraints.

Also, with respect to cost, often the last converter designconsideration is how system components will be electrically linkedtogether to form a converter topology. One particularly advantageous androbust type of linking assembly is referred to generally as a laminatedbus bar. As its label implies, a laminated bus bar typically includes aplurality of metallic sheets of laminate that are layered together withinsulators between adjacent laminate sheets. Vias are formed within thelaminated assembly where links are to be made to capacitor and switchingdevice terminals. The vias automatically link the devices and capacitorsup in a desired fashion to provide an intended converter topology (e.g.,rectifier, inverter, rectifier-inverter, etc.).

Laminated bus bar cost is generally a function of the amount of materialrequired to construct the bus, the number of laminate layers required tosupport a configuration and the overall complexity of the requiredlaminate member where minimal material, minimal layers and minimalcontours (i.e., bends in the laminates) are all advantageous.Unfortunately, providing a configuration that uses minimal laminatematerial, requires minimal layering and restricts the laminate to asingle plane is extremely difficult given the sink member configurationsrequired to minimize overall configuration size and provide essentiallyuniform heat dissipating capacity to all switching devices mounted tothe sink. For example, where devices are arranged in rows and columns toprovide similar distances between channel inlets and devices down streamtherefrom, typically a large number of laminate layers and acorrespondingly complex labyrinth of vias are required to linkcomponents together. As another instance, where switching device lengthsare aligned with similarly dimensioned capacitor lengths the laminationbus typically requires one or, more often, several bends to accommodateconnection terminals that reside in disparate planes. In either of thesetwo cases (i.e., many layers or several laminate bends) the amount ofmaterial required to configure a laminated bus bar can be excessive andhence unsuitable for certain applications.

Yet one other cost consideration related to converter assemblies has todo with component versatility or the ability to use converter componentsin more than one conversion assembly. Component versatility isparticularly important with respect to the more expensive componenttypes such as, for example, the heat sink assembly, the laminated busbar, etc. In this regard, overall system costs can be reduced bydesigning sinks and laminated bus bars that can be used with variousdevice and capacitor types. For instance, assume that a first converterassembly includes a first type of switching device, a first type ofcapacitor, a first type of sink member and a first type of laminate bar.Also assume that the sink, devices and a capacitors are dimensioned suchthat when the capacitors and devices are mounted to the sink, thecapacitors connection terminals are on the same plane as the deviceconnection terminals. Here, the first laminate bus bar type can beplanar and hence relatively inexpensive.

Next assume that a designer wants to swap out a second capacitor typefor the first type in the assembly where the second capacitor type has athickness between its dissipating surface and its connection terminalsthat is different than a similarly measures thickness of the firstcapacitor type. In this case, when the capacitors are swapped, thecapacitor and device terminals will no longer reside within the sameplane and a different, perhaps custom designed, laminate will berequired to accommodate the change. In the alternative, the sink designmay be altered to accommodate the change in device and capacitorterminal planes although this solution would be relatively expensive.Similar problems occur when different switching devices are swapped intoassemblies.

On a higher level, instead of relying on component versatility to reducecosts, if demand for a converter assembly having certain operatingcharacteristics is high enough, a complete modular converter assemblycan be efficiently (e.g., cost effectively) designed and manufactured.While high volume exists for certain small conversion assemblies,unfortunately, larger and more complex assemblies typically are not soldin volumes that justify modular, pre-manufactured, designs—there just isnot enough demand for complex larger configurations.

Even where large scale conversion assemblies having similar operatingcapabilities are in relatively high demand, often these large scaleassemblies require a relatively large space within an application. Inmany applications, while space allotted for converter components may besufficient, the allotted space may require a specially designedassembly. In other words, the space layout for a converter assembly in afirst application may be different than the space layout for a converterassembly in a second application despite similar conversion requirements(e.g., power, ripple limitations, etc.). This spatial limitation onconverter assembly versatility further limits volume requirements forlarge scale complex converter assemblies. Thus, at the high end,converter assemblies are often custom designed to meet operating andspatial layout requirements of specific applications and hence areexpensive.

Thus, it would be advantageous to have a heat sink assembly that isrelatively inexpensive to manufacture and yet provides substantiallysimilar heat dissipating capacity to all devices mounted thereto. Inaddition, it would be advantageous if a sink assembly of the above kindcould be used with a simplified laminate design and be used to configurerelatively compact converter assemblies. Moreover, it would beadvantageous if the sink assembly could be versatile and hence used withother converter components that have many different dimensions.Furthermore, it would be advantageous if a converter topologyconfigurable by using the sink assembly or a set of the sink assemblieshad many different uses such as, as an inverter, as a rectifier, as aDC-DC converter, as an AC-AC converter, etc., so that per converter unitcosts could be reduced appreciably by configuring versatile relativelylarge scale converter topologies.

BRIEF SUMMARY OF THE INVENTION

It has been recognized that relatively compact and inexpensive converterconfigurations can be configured by using an elongated liquid cooledheat sink to cool power switching devices. More specifically, it hasbeen recognized that, where switching devices are mounted in a singlerow to a sink member mounting surface, the sink can be used to configureminimal volume converter configurations. In at least one embodiment ofthe invention, the sink mounting surface has a width dimension that issubstantially similar to a width dimension of switching devices to bemounted thereto with the device width dimensions aligned with themounting surface width dimension. This single row limitation has severalconfiguration advantages described below.

It has also been recognized that, with certain types of refrigerant, thecooling capacity differential along a cooling channel appears to beexacerbated along the channel length. For instance, the cooling capacitydifferential appears to be relatively pronounced in the case of twophase refrigerants such as R-134a and R-123. As the label implies, twophase refrigerants change from a liquid to a gas when heat is absorbedand hence, generally, absorb a greater amount of heat, due to theendothermic nature of the phase change, than conventional single-phaseliquid refrigerants such as water—hence two phase refrigerants aregenerally preferred in high efficiency heat sinks.

Moreover, it has been recognized that, unfortunately, as two-phaserefrigerants absorb heat and change phase from liquid to gas, vaporbubbles are formed within the liquid that accumulate on the internalsurfaces of the heat sink and form gas pockets. The gas pockets on thesurface of the channel block refrigerant from contacting the channelsurface and hinder device heat absorption by the refrigerant. Thus, thechannel surfaces on which gas pockets form end up becoming hot spots onthe channel surfaces and the temperatures of devices attached adjacentthereto rise.

Because the vapor bubbles are formed by heat absorption and becausecoolant relatively further down stream from an inlet is warmer thancoolant more proximate the inlet, relatively more vapor bubbles areformed down stream from the inlet than proximate the inlet therebycausing more gas pockets to form down stream which increases thetemperature differential along the channel length. Thus, it has beendetermined that, while coolant temperature accounts for some of thetemperature differential along a coolant channel length, much of thetemperature differential is actually due to different amounts of gasaccumulating along different sections of the channel—the gas having aninsulating effect between the channel surfaces and the coolant passingthereby. Based on these realizations it should be appreciated that thetemperature differential problem is exacerbated where sink channels areextended.

According to several embodiments of the invention, protuberances of acharacter, quantity and size that increase turbulence within sinkchannels to a point where the turbulence either prohibits gas pocketsfrom forming on the channel surfaces or dislodges or breaks up gaspockets that form on the channel surfaces, are provided on at least oneof the channel surfaces. It has been found that when such protuberancesare provided within a channel, the channel can have an extended lengthwithout causing excessive temperature differentials there along. Morespecifically, it has been determined that the channel length can, in atleast one embodiment, extend substantially along an entire sink lengthwhere the sink, as indicated above, has a length to accommodate a singlerow of switching devices. For instance, where a converter configurationincludes twenty four switching devices, the twenty four devices can bearranged in a single row along the sink member mounting surface wherethe channel extends along substantially the entire sink length from aninlet to an outlet.

It has also been determine that, in at least some embodiments of theinvention, the sink member can be juxtaposed so that the channel inletis below the channel outlet and, more specifically, so that the channelinlet is directly vertically below the channel outlet. Here, dislodgedor broken up gas pockets, being lighter than the refrigerant, are aidedby buoyancy in their movement toward the outlet at the top of the sinkchannel.

By providing an elongated sink-device assembly including devices mountedin a single row to an elongated sink member, overall converter cost canbe reduced. In this regard, the single channel sink member can bemanufactured using the two piece sealing method described above wherethe channel is bore out of a body member, a cover member is hermeticallysealed over the channel and inlet and outlet ports that open into thechannel are formed.

In addition, cost is reduced with the inventive elongated sink-deviceassembly as a simplified laminated bus bar can be used with thesink-device assembly. In this regard, where capacitors are juxtaposed toone side of the switching devices and with capacitor terminals anddevice terminals positioned within a common connection plane, thedistances between capacitor terminals and the device terminals that thecapacitor terminals are to be linked to are reduced appreciably so thatless material is required to make terminal connections. Moreover,because capacitor terminals and the device terminals to which thecapacitor terminals are to be linked may be positioned proximate eachother, none of the laminates have to pass over other devices disposedintermediate the connecting terminals and therefore simpler laminate andassociated via designs can be employed that include relatively smallnumbers (e.g., 3) of laminate layers.

Consistent with the above, at least one embodiment of the inventionincludes an electronic converter assembly comprising a liquid cooledheat sink member having a sink length dimension, at least one mountingsurface and first and second oppositely facing lateral surfaces, themounting surface and first and second lateral surfaces forming first andsecond lateral edges, respectively, the sink member also forming atleast one internal channel that extends substantially along the entiresink length, an inlet and an outlet that open into opposite ends of thechannel, a plurality of power switching devices mounted side by side tothe mounting surface thereby forming a single device row that extendssubstantially along the sink length, each device includingintra-converter terminals that are substantially within a singleconnection plane, a plurality of capacitors, each capacitor includingcapacitor connection terminals, the capacitors linked for support to andadjacent the sink member with the capacitor terminals juxtaposedsubstantially within the connection plane and a linkage assemblyincluding a plurality of conductors that link the capacitor terminals tothe intra-converter terminals to form a power conversion topology.

In one embodiment each power switching device includes first and secondoppositely facing linking edges and wherein the intra-converterterminals form the first linking edge proximate the first lateral edgeof the sink member.

Some embodiments further include a bracket member mounted to the sinkmember and extending past the first surface, the capacitors mounted tothe bracket member for support. More specifically, the mounting surfacemay be a first mounting surface and the sink member may include a secondmounting surface that faces in a direction opposite the first mountingsurface wherein the bracket member is mounted to the second mountingsurface.

In some embodiments the bracket member includes a proximate membermounted to the second mounting surface, an intermediate member linked toand forming a substantially 90 degree angle with the proximate memberand extending substantially parallel to the first lateral side of thesink member and generally away from the sink member and a distal memberforming a substantially 90 degree angle with the intermediate member andextending generally away from the sink member, the capacitors mounted tothe distal member. Moe specifically, in one embodiment each of thedevices includes a heat dissipating surface adjacent the mountingsurface and is characterized by a device thickness dimension between theconnection plane and the dissipating surface of the device, the firstand second mounting surfaces are separated by a sink thickness, theintermediate member has an intermediate member length, each capacitorincludes first and second oppositely facing ends and a length dimensionbetween the first and second ends, the capacitor terminals extendaxially from the first end of each capacitor and the second end of eachcapacitor is mounted to the distal member and, wherein, the combinedsink thickness, device thickness and intermediate member length issubstantially similar to the capacitor length dimension.

Each capacitor may have a heat conducting extension that protrudes fromthe second end of the capacitor and that is in conductive contact withthe distal end of the bracket member. Here, the bracket member may beformed of a heat conducting material (e.g., aluminum or copper). Inaddition, here, the linkage assembly may include a substantially planarlaminated bus bar.

In some embodiments the linkage assembly links the capacitors and powerswitching devices together to form an inverter while in otherembodiments the linkage assembly may link the capacitors and switchingdevices to form a rectifier. In still other embodiments the linageassembly may link the capacitors and switching devices to form both arectifier and an inverter.

The first and second lateral edges of the mounting surface may form asink member width and a device width between the first and secondlinking edges may be substantially similar to the sink member width.

In some embodiments the channel inlet is disposed below the channeloutlet. More specifically, the channel inlet is substantially directlyvertically below the channel outlet. In some embodiments the extensionmembers may be provided that extend into the channel thereby increasingturbulence in liquid pumped from the inlet to the outlet.

The invention also includes an electronic converter assembly comprisinga heat sink member having a sink length dimension, at least one mountingsurface and first and second oppositely facing lateral surfaces, themounting surface and first and second lateral surfaces forming first andsecond lateral edges, respectively, a plurality of power switchingdevices mounted side by side to the mounting surface to form a singledevice row that extends along the sink length, each device includingintra-converter terminals juxtaposed substantially within a singleconnection plane, each device also including first and second oppositelyfacing linking edges having a device width therebetween, a bracketmember mounted to the sink member and extending past the first lateralsurface, a plurality of capacitors, each capacitor including capacitorconnection terminals, the capacitors mounted to the bracket memberadjacent the sink member with the capacitor terminals substantiallywithin the connection plane and a linkage assembly including a pluralityof conductors that link the capacitor terminals to the intra-converterterminals to form a power conversion topology.

In some embodiments the sink member forms at least one internal channelthat extends substantially along the entire sink length and an inlet andan outlet that open into opposite ends of the channel and, wherein, theconverter configuration is juxtaposed so that the channel issubstantially vertically oriented. More specifically, the channel inletmay be substantially vertically below the channel outlet.

While there are many advantages associated with arranging powerswitching devices in a single line, it has also been recognized that,under certain circumstances, such an arrangement may not function well.For example, where conversion power requirements are increased, thenumber of switching devices required to handle the power level must alsobe increased. At some point, even with an efficient and well designedliquid cooled sink, the heat generated by the devices mounted theretomay cause a temperature differential along the sink length (e.g., frominlet to outlet). Thus, there is an operational or functional limitationto liquid cooled sink length.

In addition to the functional limitation on sink length, in manyapplications there are space limitations that have to be considered whendesigning a converter configuration. For instance, while long sink andswitching configurations may be suitable for some applications, in manyapplications, space allotted for the converter assembly is rectilinearand has a short maximum dimension (e.g., the length is more similar tothe width).

According to one aspect of the present invention, a high power converterconfiguration includes two liquid cooled sink members, each memberproviding a mounting surface that may receive several (e.g., four) powerswitching device modules arranged in a line along its length. Here, asingle linking assembly links the switching devices in the modulestogether between DC buses to form conversion bridge assemblies. Inaddition, in at least some embodiments, capacitors are mounted to asingle bracket member which is in turn mounted to the sink members suchthat intra-converter module connection terminals and capacitorconnection terminals are within the same plane and a single planarlaminated bus bar links all module switches to form converter bridges.Where a long space is provided for the conversion assembly, the sinkmembers may be mounted end to end along one side of the bracket member.Where a shorter relatively more rectilinear space is provided for theconversion assembly, the bracket member may be mounted between andseparating the first and second sink members on opposite sides of thelaminated bus bar. Thus, compact high power conversion assemblies can beconfigured with minimal component count and simple component design.

In the case of a two sink configuration, each of the two sinks may havethe same design as the liquid cooled sink member described above in thecontext of a converter assembly including only a single liquid cooledsink member. Thus, converter assemblies having different capabilitiescan be configured using the same component types thereby increasingcomponent versatility and reducing per component costs.

According to another aspect of the present invention, in at least someembodiments of the invention, positive and negative DC tabs or studs arelinked to the positive and negative DC buses of a laminated bus bar. TheDC tabs increase complex converter assembly versatility and thereby toreduce per assembly costs. For instance, an exemplary complex converterassembly may include first and second sets of power switching devicemodules where each module includes six switching devices (i.e., eachmodule independently includes all of the switching devices required toconstruct a complete converter bridge). A laminated intra-converter busbar links all of the device modules together so that a plurality ofseparate converter bridges are formed between positive and negative DCbuses where each bridge includes first, second and third switch pairs,each pair arranged in series between the DC buses. Each of three busbars in a first inter-converter bar set may be linked to the positiveand negative DC buses in the laminated bar via the switches in at leastone bridge leg (e.g., each inter-converter bar is linked to at least onecommon node between the two switches in a single switch pair). Here, DCtabs extend from the positive and negative DC buses in the laminate.

The above complex converter topology can be employed to provide variousdifferent conversion functions. For example, the first inter-converterbar set may be linked to an AC source, the second inter-converter barset may be linked to a load and the switching devices in the first andsecond module sets may be controlled so that the topology provides AC-ACconversion (i.e., as a rectifier and an inverter)—in this case the DCtabs are not employed. As another example, the first inter-converter barset may be linked to an AC source, the second bar set may not be linkedto either a source or a load and the DC tabs may then be employed as aDC source for some other application. Similarly, each of the first andsecond inter-converter bar sets may be linked to AC sources and each ofthe first and second module sets may be controlled as rectifiers toprovide a higher DC voltage at the DC tabs. As one other example, anexternal DC source may be provided at the DC tabs and both or only oneof the module sets may be controlled as inverters to provide AC outputvoltages at associated inter-converter bars. Still another example mayinclude, where each module set includes more than one module,controlling only a sub-set of the first or second set modules to rectifyor inverter power where lesser power levels are required.

It should be appreciated that, while the industry generally has lookedupon relatively large conversion topologies with a jaundiced eye becauseof a lack of versatility and because of limitations regardingaccommodating space layouts, by combining the inventive liquid cooledsink member concepts with specific component juxtapositions and the DCtab concept, far smaller and far more versatile complex converterassemblies can be designed and manufactured.

While various aspects of the present invention render complex convertertopologies cost effective and small enough to be suitable for manyapplications, one additional problem occurs when multiple powerswitching device modules are combined to increase rectifier and/orinverter power handling capabilities. In this regard, as known in theswitching device industry, despite efforts to manufacture switchingdevices that have identical operating characteristics, unfortunately,operating characteristics for devices of the same type are oftenslightly different such that turn on and off periods for the switchingdevices vary within a “tolerance range”. In the case of convertercontrol, a huge number of switching operations occur every second andthe cumulative effect of the switching differences has been known toappreciably and adversely affect conversion functions.

It has been recognized that, while switches of a specific type may haveoperating characteristics that fall within some specified range, therange of operating characteristics for switches mounted on the sameswitching device module is typically smaller than the range ofcharacteristics of devices on different switching device modules. Forinstance, in the case of first and second modules of the same type, theoperating characteristics of the six switching devices on the firstmodule will typically be within a first small range and the operatingcharacteristics of the six switching devices on the second module willtypically be grouped within a second small range where the first andsecond ranges are different.

According to another aspect of the present invention, inter-converterbus bars have been designed wherein each bus bar links to switchingdevices on several different switching device modules so that thedifferent switching device operating characteristics can be averagedamong the different converter phases. For instance, in at least someembodiments of the invention where two modules are used to link first,second and third inter-converter bus bars to DC buses, each of the busbars is linked to a separate switching device pair in each of themodules (e.g., a first bar may be linked to the common node of a firstswitching device pair in each of the first and second modules, a secondbar may be linked to the common node of a second switching device pairin each of the first and second modules and a third bar may be linked tothe common node of a third switching device pair in each of the firstand second modules). Where additional modules are used to link theinter-converter bars to the DC buses, each bar is linked to a devicepair in each of the additional modules.

Consistent with the above, the present invention also includes anelectronic converter assembly comprising first and second liquid cooledheat sink members, each sink member having at least one sink mountingsurface, first and second pluralities of power switching devices, eachswitching device including connection terminals, the first and secondpluralities of switching devices mounted to the first and second sinkmounting surfaces, respectively and a planar laminated bus bar includinga plurality of conductors that link the power switching deviceconnection terminals to form a power conversion topology.

In some embodiments further include a bracket member and a plurality ofcapacitors, the bracket member having at least one bracket mountingsurface and rigidly mounted to each of the first and second sinkmembers, the capacitors mounted to the bracket mounting surface and thelaminated bar further linking the switching device connection terminalsand the capacitors to form the conversion topology. Here, the bracketmember may be mounted between the first and second sink members andfirst lateral surfaces of the first and second sink members may faceeach other. Moreover, each capacitor may include a mounting end and acapacitor connection terminal at an end opposite the mounting end, maybe mounted to the bracket mounting surface at the mounting end and maybe dimensioned such that the connection terminal is substantiallycoplanar with the switching device connection terminals.

In at least some embodiments the bracket member includes first andsecond lateral end members mounted to the second mounting surfaces ofthe first and second sink members, respectively, first and secondintermediate members linked to and forming substantially 90 degreeangles with the first and second proximate members and extendingsubstantially parallel to the first lateral sides of the first andsecond sink members and generally away from the first and second sinkmembers, respectively, and a central member linked between the first andsecond intermediate members, forming a substantially 90 degree anglewith each of the intermediate members and extending generally betweenthe first and second sink members, the capacitors mounted to the centralmember. Here, each of the devices includes a heat dissipating surfaceadjacent the mounting surface and is characterized by a device thicknessdimension between the connection plane and the dissipating surface ofthe device, the first and second mounting surfaces on each of the sinkmembers are separated by a sink thickness, each of the first and secondintermediate members has an intermediate member length, each capacitorincludes first and second oppositely facing ends and a length dimensionbetween the first and second ends, the capacitor terminals extendaxially from the first end of each capacitor and the second end of eachcapacitor is mounted to the central member and, wherein, the combinedsink thickness, device thickness and intermediate member length issubstantially similar to the capacitor length dimension.

In some cases the first sink member has a first length dimension andforms a first internal channel along its length dimension between aninlet and an outlet and wherein the second sink member has a secondlength dimension and forms a second internal channel along its lengthdimension between an inlet and an outlet. The sink members may beoriented such that the first sink member inlet is below the first sinkmember outlet and the second sink member inlet is below the second sinkmember outlet. More specifically, the sink members may be oriented suchthat the channels are substantially vertically oriented.

In some embodiments each of the first and second sink members has firstand second oppositely facing lateral surfaces, the mounting surfaces andfirst and second lateral surfaces form first and second lateral edges,respectively, on each of the sink members, the bracket member mounted tothe sink members such that the first lateral surfaces of the first andsecond sink members oppose each other. In a particularly detailedconfiguration the first plurality of power switching devices is mountedside by side on the first sink mounting surface forming a single rowthat extends substantially along the first sink length, each device inthe first plurality including intra-converter terminals juxtaposedwithin a first connection plane and wherein the second plurality ofpower switching devices is mounted side by side on the second sinkmounting surface forming a single row that extends substantially alongthe second sink length, each device in the second plurality includingintra-converter terminals that are also juxtaposed within the firstconnection plane wherein the intra-converter connection terminals arethe terminals linked to the laminated bus bar.

The intra-converter terminals of each device may be located proximatethe first lateral edge of the sink member to which the device ismounted. Similarly, the inter-converter terminals of each device may belocated proximate the second lateral edge of the sink member to whichthe device is mounted and are within the first connection plane.

The invention also includes an electronic converter assembly comprisingfirst and second liquid cooled heat sink members, each sink memberhaving at least one sink mounting surface and a length dimension, eachsink member forming an internal substantially vertical channel betweenan inlet and an outlet where the inlet is below the outlet, a bracketmember rigidly linked to the first and second sink members, first andsecond pluralities of power switching devices mounted to the first andsecond sink mounting surfaces, respectively, each switching deviceincluding intra-converter connection terminals and a linkage assemblyincluding a plurality of conductors that link the power switching deviceintra-converter connection terminals to form a power conversiontopology. In some embodiments the bracket member is mounted between thefirst and second sink members.

The invention also includes a method for configuring a converterassembly, the method comprising the steps of providing first and secondliquid cooled heat sink members where each member has a mounting surfaceand has a length dimension, each mounting surface having first andsecond lateral edges that extend along the length dimension and thatface in opposite directions, mounting a bracket member to the sinkmembers such that the sink member length dimensions are substantiallyparallel, providing first and second pluralities of power switchingdevices where each device includes inter-converter connection terminalsto be linked to a source or a load and intra-converter connectionterminals to be linked to either a positive or a negative DC bus,mounting the first and second pluralities of switching devices to thefirst and second sink member mounting surfaces with the intra-converterand the inter-converter connection terminals proximate the first andsecond edges of the mounting surfaces, respectively and linking theintra-converter connection terminals to positive and negative DC busesto form the converter topology.

In some cases the step of mounting the bracket member to the sinkmembers includes mounting the bracket member between the first andsecond sink members such that the first edges of the sink members faceeach other. In some cases the method further includes the step oforienting the first and second sink members such that the lengthdimensions are substantially vertically oriented. In some embodimentsthe step of linking includes providing a laminated bus bar includingpositive and negative DC bus conducting layers and linking theintra-converter connection terminals to the positive and negative layersto configure the topology.

The invention also includes an apparatus for linking together powerswitching devices having intra-converter connection terminals to form apower conversion assembly, the apparatus comprising a planar laminatedbus bar including positive and negative DC bus layers and insulatinglayers that insulate each of the DC bus layers, the bar also includingat least a first external insulating layer that forms a first externalsurface of the bar, the bar also forming at least first and secondlinking edges and first and second pluralities of linkages formed alongthe first and second linking edges, respectively, each linkage linked toone of the positive and negative DC bus layers and configured to belinkable to at least one of the power switching device intra-converterconnection terminals.

In some of the embodiments each of the linkages is a linking tab. Insome cases the first and second edges of the bus bar face in oppositedirections. In some embodiments the bus bar is substantiallyrectilinear. In some embodiments the first and second edges are straightand the first plurality of linkages are aligned along the first straightedge and the second plurality of linkages are aligned along the secondstraight edge. In some cases the first and second linking edges arevertically aligned.

Some cases include first and second external linking vias that open tothe positive and negative DC bus layers, respectively. Some embodimentsfurther include positive and negative DC connection terminals thatextend through the first and second vias and are linked to the positiveand negative DC bus layers, distal ends of the DC connection terminalsexposed and connectable to at least one of a DC source and a DC load.

According to one aspect the apparatus is for linking at least first andsecond bridge assemblies together with capacitors to form a conversiondevice wherein, each of the linkages in the first plurality is linked toat least one of the intra-converter connection terminals of the firstbridge assembly and each of the linkages in the second plurality islinked to at least one of the intra-converter connection terminals ofthe second bridge assembly.

The invention further includes a three phase electronic converterassembly comprising at least a first heat sink member having a mountingsurface, first and second X phase converter bridge assemblies, eachbridge assembly including a plurality of power switching devices, thefirst bridge assembly forming first through Xth external linkageterminals and the second bridge assembly forming (X+1)th through 2Xthexternal linkage terminals, each linkage terminal linkable to one phaseof at least one of an X phase source and an X phase load, the switchingdevices mounted to the mounting surface of the at least first sinkmember, a plurality of capacitors and a laminated bus bar including apositive DC bus, a negative DC bus and a plurality of insulating layersthat insulate the positive and negative DC buses and form an externalinsulating layer, the linkage assembly linking the plurality ofcapacitors and each of the bridge assemblies between the positive andnegative DC buses, the bar forming first and second external linkingvias that open to the positive and negative DC buses, respectively.

The invention moreover includes a three phase electronic converterassembly comprising a first heat sink member having a mounting surface,a second heat sink member having a mounting surface, first and second Xphase converter bridge assemblies, each bridge assembly including aplurality of power switching devices, the first bridge assembly formingfirst through Xth external linkage terminals and the second bridgeassembly forming (X+1)th through 2Xth external linkage terminals, eachlinkage terminal linkable to one phase of at least one of an X phasesource and an X phase load, the first assembly switching devices mountedto the first sink member mounting surface and the second assemblyswitching devices mounted to the second sink member mounting surface, aplurality of capacitors and a laminated bus bar including a positive DCbus, a negative DC bus and a plurality of insulating layers thatinsulate the positive and negative DC buses and form an externalinsulating layer, the linkage assembly linking the plurality ofcapacitors and each of the bridge assemblies between the positive andnegative DC buses, the external insulating layer forming first andsecond vias that open to the positive and negative DC buses,respectively.

Consistent with another aspect of the invention, an electronic converterassembly may comprise a first heat sink member having at least a firstmounting surface and a length dimension, a plurality of power switchingdevice modules wherein each module includes at least four separate powerswitching devices, the modules mounted to the first sink mountingsurface such that the switching devices are aligned along the length ofthe sink member, each switching device including inter-converterconnection terminals linkable to at least one of a load and a source andintra-converter connection terminals linkable, each intra-converterconnection terminal linkable to at least one of a positive and anegative DC bus, first, second and third bus bars, each bus bar linkedto the inter-converter connection terminals of at least first and secondpairs of the power switching devices where the at least first and secondpairs of power switching devices linked to specific ones of the bus barsare from different switching device modules and a linkage assemblyincluding a plurality of conductors that link the intra-converterconnection terminals of the power switching devices to form a powerconversion topology.

Some embodiments further include fourth, fifth and sixth bus bars and,wherein, the linkage assembly links the intra-converter connectionterminals to form at least first and second converter bridges, thefirst, second and third bus bars linked to the inter-converterconnection terminals of the switching devices that form the firstconverter bridge and the fourth, fifth and sixth bus bars linked to theinter-converter connection terminals of the switching devices that formthe second converter bridge.

In some cases the modules include at least first and second modules,each of the modules includes first, second, third, fourth, fifth andsixth switching devices aligned in a row where the first and seconddevices form a first device pair, the third and fourth devices form asecond device pair and the fifth and sixth devices form a third devicepair on each module, the linkage assembly linking the intra-converterconnection terminals of each of the first, third and fifth switchingdevices in each module to a positive DC bus and linking theintra-converter connection terminals of each of the second, fourth andsixth switching devices in each module to a negative DC bus, the firstbus bar linked to the inter-converter connection terminals of the firstpair of devices of each module, the second bus bar linked to theinter-converter connection terminals of the second pair of devices ofeach of each module and the third bus bar is linked to theinter-converter connection terminals of the third pair of devices ofeach of each module. In other cases the modules further include a thirdmodule that includes first, second, third, fourth, fifth and sixthswitching devices, the linking assembly further linking theintra-converter connection terminals of each of the first, third andfifth switching devices in the third module to the positive DC bus andlinking the intra-converter connection terminals of each of the second,fourth and sixth switching devices in the third module to the negativeDC bus, the first bus bar also linked to the inter-converter connectionterminals of the first and second switching devices of the third module,the second bus bar linked to the inter-converter connection terminals ofthe third and fourth switching devices of the third module and the thirdbus bar linked to the inter-converter connection terminals of the fifthand sixth switching devices of the third module. In still another casethe modules further include a fourth module that includes first, second,third, fourth, fifth and sixth switching devices, the linking assemblyfurther linking the intra-converter connection terminals of each of thefirst, third and fifth switching devices in the fourth module to thepositive DC bus and linking the intra-converter connection terminals ofeach of the second, fourth and sixth switching devices in the fourthmodule to the negative DC bus, the first bus bar also linked to theinter-converter connection terminals of the first and second switchingdevices of the fourth module, the second bus bar linked to theinter-converter connection terminals of the third and fourth switchingdevices of the fourth module and the third bus bar linked to theinter-converter connection terminals of the fifth and sixth switchingdevices of the fourth module.

In some embodiments the first through fourth modules are a first moduleset, the apparatus further including a second heat sink member, a secondmodule set and fourth, fifth and sixth bus bars, the second sink memberhaving at least a first mounting surface and a length dimension, thesecond module set including fifth through eighth power switching devicemodules, the fifth through eighth modules mounted to the second sinkmounting surface such that the switching devices that comprise thesecond module set are aligned along the length of the second sinkmember, the linkage assembly linking the intra-converter connectionterminals of each of the first, third and fifth switching devices ineach module to a positive DC bus and linking the intra-converterconnection terminals of each of the second, fourth and sixth switchingdevices in each module to a negative DC bus, the fourth bus bar linkedto the inter-converter connection terminals of the first and secondswitching devices on each of the fifth, sixth, seventh and eighthmodules, respectively, the fifth bus bar linked to the inter-converterconnection terminals of the third and fourth switching devices on eachof the fifth, sixth, seventh and eighth modules, respectively, the sixthbus bar linked to the inter-converter connection terminals of the fifthand sixth switching devices on each of the fifth, sixth, seventh andeighth modules, respectively.

Some embodiments further include a bracket member and a plurality ofcapacitors, the bracket member rigidly mounted between and separatingthe first and second heat sink members and having a bracket mountingsurface that faces in the same direction as each of the first and secondsink mounting surfaces, the capacitors mounted to the bracket mountingsurface and linked to the linkage assembly conductors to form a part ofthe conversion topology.

In some cases the first bus bar includes a first bus spine member and aplurality of first bus rib members linked to the first spine member andextending laterally therefrom, each of the first rib members linked toat least two of the inter-converter terminals on one of the devicemodules and linked to no more than two inter-converter terminals on eachof the device modules, the second bus bar including a second bus spinemember and a plurality of rib members linked to the second bus spinemember and extending laterally therefrom, each of the second rib memberslinked to at least two of the inter-converter terminals on one of thedevice modules and linked to no more than two inter-converter terminalon each of the device modules, the third bus bar including a third busspine member and a plurality of rib members linked to the third spinemember and extending laterally therefrom, each of the third rib memberslinked to at least two of the inter-converter terminals on one of thedevice modules and linked to no more than two inter-converter terminalon each of the device modules. In some embodiments each of the modulesincludes first, second, third, fourth, fifth and sixth switching devicesand, wherein, the first bus bar includes a separate rib member for eachpair of first and second switching devices in each of the modules, thesecond bus bar includes a separate rib member for each pair of third andfourth switching devices in each of the modules and the third bus barincludes a separate rib member for each pair of fifth and sixthswitching devices in each of the modules.

The invention further includes an electronic converter assemblycomprising a heat sink member having at least a first mounting surface,a length dimension and first and second oppositely facing lateralsurfaces that extend parallel to the length dimension, the mountingsurface and first and second lateral surfaces forming first and secondlateral edges, respectively, first, second, third and fourth powerswitching device modules wherein each module includes first, second,third, fourth, fifth and sixth separate power switching devices, eachswitching device including inter-converter connection terminals andintra-converter connection terminals that extend from the device inopposite directions, the modules mounted to the sink mounting surfacesuch that the switching devices are aligned along the length of the sinkmember with the intra-converter connection terminals proximate the firstlateral edge and the inter-converter terminals proximate the secondlateral edge and first, second and third bus bars, each of the bus barslinked to a sub-set of the connection terminals of switching devices inat least two different device modules.

Other embodiments include an electronic converter assembly comprising afirst heat sink member having at least a first mounting surface, alength dimension and first and second oppositely facing lateral surfacesthat extend parallel to the length dimension, the mounting surface andfirst and second lateral surfaces forming first and second lateraledges, respectively, a second heat sink member having at least a firstmounting surface, a length dimension and first and second oppositelyfacing lateral surfaces that extend parallel to the length dimension,the mounting surface and first and second lateral surfaces of the secondsink member forming first and second lateral edges, respectively, firstand second module sets, the first module set including first, second,third and fourth power switching device modules and the second moduleset including fifth, sixth, seventh and eighth power switching devicemodules wherein each module includes first, second, third, fourth, fifthand sixth separate power switching devices, each switching deviceincluding inter-converter connection terminals and intra-converterconnection terminals that extend from the associated module in oppositedirections, the modules in the first module set mounted to the firstsink member mounting surface such that the switching devices are alignedalong the length of the first sink member, the intra-converterconnection terminals proximate the first lateral edge and theinter-converter terminals proximate the second lateral edge of the firstsink member, the modules in the second module set mounted to the secondsink member mounting surface such that the switching devices are alignedalong the length of the second sink member, the intra-converterconnection terminals proximate the first lateral edge and theinter-converter terminals proximate the second lateral edge of thesecond sink member, first, second, third, fourth, fifth and sixth busbars, each of the first, second and third bus bars linked to theinter-converter connection terminals of switching devices in at leasttwo different device modules in the first module set and each of thefourth, fifth and sixth bus bars linked to the inter-converterconnection terminals of switching devices in at least two differentdevice modules in the second module set and a linkage assembly linkingthe intra-converter connection terminals of the switches in each of thefirst, second, third, fourth, fifth, sixth, seventh and eighth modulestogether to form the converter topology.

The invention also includes a bus bar assembly for use with anelectronic converter assembly having a plurality of switching devicemodules, each module including first, second and third pairs of powerswitching devices, each pair including a first device linked to apositive DC bus and a second device linked to a negative DC bus, thefirst and second devices of each pair having adjacent inter-converterconnection terminals aligned along an edge of the sink member, theassembly comprising a first rigid bus bar linkable to theinter-converter connection terminals of the first pair of switchingdevices in each module, a second rigid bus bar linkable to theinter-converter connection terminals of the second pair of switchingdevices in each module and a third rigid bus bar linkable to theinter-converter connection terminals of the third pair of switchingdevices in each module.

These and other objects, advantages and aspects of the invention willbecome apparent from the following description. In the description,reference is made to the accompanying drawings which form a part hereof,and in which there is shown a preferred embodiment of the invention.Such embodiment does not necessarily represent the full scope of theinvention and reference is made therefore, to the claims herein forinterpreting the scope of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1a is a schematic diagram of a rectifier configuration andcorresponding controller while FIG. 1b is a schematic diagram of aninverter configuration;

FIG. 2 is an exploded perspective view of a converter assembly accordingto one embodiment of the present invention;

FIG. 3 is an exploded perspective view of the heat sink member andswitch packages of FIG. 2;

FIG. 4 is a side plan view of an assembled configuration consistent withFIG. 2;

FIG. 5 is a bottom plan view of the conversion configuration of FIG. 4;

FIG. 6 is a plan view of the body member of the heat sink member of FIG.3 and, in particular, showing the surface of the body member in which acoolant channel is formed;

FIG. 7 is similar to FIG. 6, albeit illustrating a second embodiment ofthe body member;

FIG. 8 is similar to FIG. 6, albeit illustrating yet one otherembodiment of the body member;

FIG. 9 is a flow chart according to one aspect of the present invention;

FIG. 10a a schematic diagram of a rectifier configuration andcorresponding controller while FIG. 10b is a schematic diagram of ainverter configuration;

FIG. 11 is an exploded perspective view of a converter assemblyaccording to one embodiment of the present invention;

FIG. 12 is a side plan view of an assembled configuration consistentwith FIG. 11;

FIG. 13 is a top plan view of the converter configuration of FIG. 12;

FIG. 14 is a schematic diagram similar to the diagram illustrated inFIG. 10a, albeit illustrating a different linkage pattern of input linesto common nodes;

FIG. 15 is a schematic diagram illustrating switching modules and asecond bus bar embodiment;

FIG. 16 is similar to FIG. 15, albeit illustrating a third embodiment ofan inventive bus bar configuration;

FIG. 17 is a cross-sectional view of a bus bar showing vias andextending external positive and negative linkage terminals;

FIG. 18 is a flow chart illustrating a method of configuring a versatileconverter topology according to the one aspect of the present invention;and

FIG. 19 is a schematic top plan view diagram of an additional converterconfiguration according to one aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings where in like numerals correspond tosimilar elements throughout the several views and, more specifically,referring to FIGS. 1a and 1 b, the present invention will be describedin the context of exemplary motor control system 10 including arectifier assembly generally illustrated in FIG. 1a which feeds aninverter assembly generally illustrated in FIG. 1b where each of therectifier and inverter are controlled by a controller 22. As known inthe controls industry, rectifier (FIG. 1a) receives three-phase ACvoltage on input lines 12, 14 and 16 and converts that three-phasevoltage to a DC potential across positive and negative DC buses 18 and20, respectively. The DC buses 18 and 20 generally feed the inverterconfiguration (see again FIG. 1b) which converts the DC potential tothree-phase AC voltage waveforms that are provided to a three-phase loadvia first, second and third inverter output lines 24, 26 and 28,respectively.

The rectifier assembly includes twelve separate switching devicesidentified by numerals 30-41. The switching devices 30-41 are arrangedbetween the positive and negative DC buses 18 and 20, respectively, toprovide six separate rectifier legs. Each rectifier leg includes twoseries connected switching devices that traverses the distance betweenthe positive and negative DC buses 18 and 20, respectively. For example,a first rectifier leg includes switches 30 and 36 that are in seriesbetween positive bus 18 and negative bus 20, a second rectifier legincludes switches 31 and 37 that are series connected between buses 18and 20, a third rectifier leg includes switches 32 and 38 that areseries connected between buses 18 and 20, and so on. The nodes betweenswitches in each rectifier leg are referred to as common nodes. Onecommon node between switches 32 and 38 is identified by numeral 46.

Each of input lines 12, 14 and 16 is separately linked to two differentcommon nodes. For example, as illustrated, line 14 is linked to commonnode 46 between switches 32 and 38 and is also linked to the common node(not numbered) between switches 33 and 39. In a similar fashion, inputline 12 is linked to the common node between switches 34 and 40 and alsoto the common node between switches 35 and 41 while line 16 is linked tothe common node between switches 30 and 36 and to the common nodebetween switches 31 and 37. In FIG. 1a (and also FIG. 1b describedbelow) switch emitters, collectors and gates are identified via E, C andG labels, respectively, with the collectors and emitters of switches 30and 36 qualified by “1” and “2” sub-labels (e.g., E1, E2, C1, C2), todistinguish those emitters and collectors for additional explanationbelow.

A control bus 48 which represents a plurality of different control lineslinks controller 22 separately to each one of the rectifier switches30-41 for independent control. Controller 22 controls when each of theswitches 30-41 turns on and when each of the switches 30-41 turns off.Control schemes that may be used by controller 22 to convert thethree-phase voltages on lines 12, 14 and 16 to a DC potential across DCbuses 18 and 20 are well known in the conversion art and therefore willnot be described herein detail. Rectifier legs that have their commonnodes (e.g., 46) linked to the same input line are controlled in anidentical fashion by controller 22. For example, referring still to FIG.1a, each of switches 32 and 33 would be turned on and turned off at thesame time by controller 22 and each of switches 38 and 39 would beturned on and turned off at the same times by controller 22 as thecorresponding rectifier legs have the same common node 46 linked to line14.

In addition to the components described above, the rectifierconfiguration illustrated in FIG. 1a also includes capacitors between DCbuses 18 and 20 which are collectively identified by numeral 50.Although only two capacitors are illustrated, it should be appreciatedthat a larger number of capacitors would typically be employed in anytype of rectifier configuration. Capacitors 50 reduce the ripple in thepotential between lines 18 and 20 as well known in the art.

Referring now to FIG. 1b, the inverter configuration illustrated, likethe rectifier configuration of FIG. 1a, includes twelve separateswitching devices identified by numerals 61-72. The switching devices61-72 are arranged to form six separate inverter legs. Each inverter legincludes a pair of the switching devices 61-72 that is series arrangedbetween the positive DC bus 18 and the negative DC bus 20. For example,a first inverter leg includes switches 61 and 67 series arranged betweenbuses 18 and 20, a second inverter leg includes switches 62 and 68series arranged between buses 18 and 20, a third leg includes switches63 and 69 series arranged between buses 18 and 20, and so on.

Common nodes between inverter leg switch pairs are referred tohereinafter as common nodes. In FIG. 1b, an exemplary common nodebetween switches 61 and 67 is identified by numeral 80. In theillustrated embodiment, each output line 24, 26 and 28 is linked to twoseparate inverter leg common nodes (e.g., 80). For example, output line28 is linked to common node 80 between switches 61 and 67 and is alsolinked to the common node (not illustrated) between switches 62 and 68.Similarly, output line 26 is linked to the common node between switches63 and 69 and also to the common node between switches 64 and 70 whileoutput line 24 is linked to the common node between switches 65 and 71and is also linked to the common node between switches 66 and 72.

The control bus 48 linked to controller 22 is also linked separate toeach of the inverter switches 61-72 to independently control the turn onand turn off times of those switches. As in the case of the rectifierswitches of FIG. 1a, controller 22 controls the switches of the inverterlegs that have common nodes linked to the same output line in anidentical fashion. To this end, referring still to FIG. 1b, because thecommon nodes (e.g., 80) corresponding to the first inverter legincluding switches 61 and 67 and the second inverter leg includingswitches 62 and 68 are both connected to output line 28, the first andsecond inverter legs are controlled in a similar fashion so that each ofswitches 61 and 62 is turned on and turned off at the same times andeach of switches 67 and 68 are turned on and off at the same times.

Referring to FIGS. 1a and 1 b, the rectifier-inverter configurationincludes commonly controlled switches so that the configuration canhandle relatively high currents that may otherwise destroy the types ofdevices employed to configure the converters. In this manner relativelyless expensive switches can be used to construct the converter assembly.The switches 30-41 used to configure the rectifier are typicallyidentical and the switches 61-72 used to configure the inverter aretypically identical. Depending on the configuration design, switches30-41 may or may not be identical to switches 61-72.

Referring still to FIGS. 1a and 1 b, switch manufacturers often providepower switching devices in prepackaged modules suitable to constructinverters and rectifiers. To this end, often, a complete 6-switch bridgewill be provided as a separate and unique switching power package.Hereinafter it will be assumed that the 24 switches that comprise therectifier and inverter in FIGS. 1a and 1 b are provided in four separate6-switch bridge packets where the first switching package includesswitches 30, 31, 32, 36, 37 and 38, the second switch package includesswitches 33, 34, 35, 39, 40 and 41, the third switch package includesswitches 61, 62, 63, 67, 68 and 69 and the fourth switch packageincludes switches 64, 65, 66, 70, 71 and 72. Unless indicated otherwise,hereinafter, the first, second, third and fourth switch packages will beidentified by numerals 90, 92, 94 and 96, respectively. Exemplary switchpackets 90, 92, 94 and 96 are illustrated in FIG. 2 and are described ingreater detail below.

Referring now to FIG. 2, an exploded perspective view of an exemplaryrectifier/inverter converter assembly 100 is illustrated. Configuration100 includes a heat sink member 102, the four power switching devicemodules 90, 92, 94 and 96 briefly described above, a bracket member 104,a plurality of capacitors collectively identified by numeral 50, alaminated bus bar 106 and a plurality of input and output bus barsidentified by numerals 12′, 14′, 16′, 28′, 26′, and 24′.

Each of switch packages 90, 92, 94 and 96 is similarly constructed andtherefore, in the interest of simplifying this explanation, unlessindicated otherwise, only switch package 90 will be described here indetail. Referring also to FIGS. 3 and 5, package 90 has a generallyrectilinear shape having a length dimension L3, a width dimension W1 anda thickness dimension (not separately labeled). Although not illustratedin any of the drawings, device package 90 is characterized by a devicethickness dimension that will be referred to herein by label T1 that isformed between the mounting or dissipating surface 122 (see FIG. 3) ofthe device and a connection plane defined by the top surfaces of theemitter and capacitor connection terminals that extend from the packagehousing. Package 90 has a first device or first linking edge 130 and asecond device or second linking edge 132 that face in oppositedirections and are separated by device width W1 as illustrated.

Referring still to FIG. 1a and also to FIG. 2, package 90 includesswitching devices 30, 31, 32, 36, 37 and 38 that are arranged in asingle row relationship where the emitters and collectors for each oneof the switching devices extend from opposite side of package 90 and aregenerally separated by the device width W1. For example, the emitter E1and collector C1 extend from opposite sides of package 90 while emitterE2 and collector C2 for switch 36 extend in opposite directions.Adjacent switches within package 90 have their emitters and collectorsextending in different directions. For example, referring to FIG. 1a andFIG. 2, switch 36 in FIG. 1a has its emitter E2 and its collector C2extending in directions opposite those of emitter E1 and collector C1 ofthe first switch 30 adjacent thereto in the package 90. Referring stillto FIG. 3, package 90 is designed so that all of the emitter andcollector terminals extend from the package housing within a singleconnection plane.

Hereinafter, unless indicated otherwise, switching device connectionterminals that are linked to any of bus bars 12′, 14′, 16′, 24′, 26′ or28′ will be referred to as inter-converter terminals because thoseterminals are connected through their respective bus bars to componentsoutside the converter configuration. Similarly, any device packageterminals that are linked to laminated bus bar 106 will be referred tohereinafter generally as intra-converter terminals as those terminalsare linked to other components within the converter assembly.

As illustrated and described hereinafter, all of the inter-converterterminals extend from one side of package 90 while all of theintra-converter terminals extend from the opposite side of package 90after the configuration in FIGS. 2 and 4 is assembled. In addition,after assembly, all of the intra-converter terminals for all of packages90, 92, 94 and 96 extend in the same direction and form a connectionline while all of the inter-converter terminals for packages 90, 902,904 and 96 extend in the opposite direction and form a second connectionline (see alignment generally in FIG. 2). The first and secondconnection lines form linking edges of the devices in the packages.

Control ports are provided on a top surface of package 90 to facilitatelinking of control bus 48 to the devices provided within package 90. Anexemplary control port in FIG. 2 is identified by numeral 120.

Package 90 has an undersurface 122 that is in thermal contact with thecomponents inside the package housing that generate heat. Package 90 isdesigned so that surface 122 is substantially flat and can makesubstantially full contact with a heat sink surface when mountedthereto. It should be appreciated that, typically, only a portion ofsurface 122 may generate a relatively large percentage of the totalamount of heat generated by the package and that the primary heatgenerating surface will likely be the central portion of surface 122. Aheat generating segment 124 or dissipating surface of package 92 isillustrated and includes a space that is framed by an outer space 126that surrounds the heat generating space 124. Space 124 generallycorresponds to a space that is in direct contact with the package 90components that conduct current and hence generate heat. Space 124 has adissipating surface width dimension W2 associated therewith.

As best in seen in FIGS. 2 and 3, each package 90 includes a pluralityof small apertures, two of which are identified by number 128, providedthrough the outer space 126 that frames the heat generating segment 124(e.g., see device 92) as illustrated. Apertures 128 are provided tofacilitate mounting packages 90, 92, 94 and 96 to sink member 102.

Referring still to FIG. 2, bus bars 12′, 14′, 16,′ 28′, 26′ and 24′ areto be linked to input lines 12, 14, 16 and output lines 28, 26 and 24 inFIGS. 1a and 1 b, respectively. The linking relationship between busbars and associated lines is highlighted by the bus bars being labeledwith numbers that are identical to the line numbers to which theyconnect followed by a “′” indicator.

Each of input and output bus bars 12′, 14′, 16′, 24′, 26′ and 28′ aresimply steel bars that either have an “L” shape or a “T” shape. Each bar12′, 14′, 16′, 24′, 26′ and 28′ is designed to link input or outputlines to a subset of four of the inter-converter terminals. For example,referring to FIGS. 1a and 2, L-shaped bus bar 16′ is constructed anddimensioned so as to link together each of the emitter E1 for switch 30,the collector C2 for switch 36, the emitter for switch 31 and thecollector for switch 37 and, to this end, includes four separateapertures for receiving some type of mechanical securing component(e.g., a bolt), a separate aperture corresponding to each one theemitters and collectors to be connect by bar 16′. Each of the other busbars 12′, 14′, 24′, 26′ and 28′ has a construction similar to bus bar16′ and therefore, in the interest of simplifying this explanation, theother bars will not be described here in detail. It should suffice tosay that the bus bars link emitters and collectors among the switchpackages 90, 92, 94 and 96 in a manner that is consistent with theschematics illustrated in FIGS. 1a and 1 b.

Referring once again to FIG. 3 and also to FIG. 4, heat sink member 102is an elongated and, in the illustrated embodiment, substantiallyrectilinear metallic (e.g., aluminum, copper, etc.) member that extendsfrom a first end 144 to a second end 146, has first and second lateralsurfaces 148 and 150, respectively, that face in opposite directions andextend along the entire length between ends 144 and 146 and alsoincludes a first or first mounting surface 140 and a second oppositelyfacing mounting surface 142. As best illustrated in FIG. 2 (and alsoillustrated in FIG. 6), mounting surface 140 has a width dimension W3that separates the lateral surfaces 148 and 150, respectively and has alength dimension L5. Mounting surface 140 and lateral surfaces 148 and150 form first and second lateral edges 149 and 151, respectively. In atleast one embodiment of the present invention, sink width W3 issubstantially similar to the device package width W1 so that, asillustrated in FIG. 2, device packages 90, 92, 94 and 96 are mounted ina side-by-side single row fashion to be accommodated on mounting surface140.

As best seen in FIG. 3, in at least one embodiment, sink member 102includes two separate components that are secured together. The twocomponents including a body member 160 and a cover member 162. Referringalso to FIG. 5, body member 160 has thickness dimension T2 which isgenerally greater than the thickness dimension (not separatelyidentified) of member 162. Together, body member 160 and cover member162 have a thickness dimension T3.

As illustrated in FIGS. 3 and 6, body member 160 includes a secondsurface 164 opposite mounting surface 140 and forms a cavity 166 thereinwhich extends substantially along the length of body member 160 from thefirst end 144 of the sink member to the second end 146. Cavity 166 has acavity or channel depth Dc and forms a cavity or channel surface 69. Inthe illustrated embodiment, cavity 166 stops short of each of the ends140 and 146, has a cavity length dimension L4 and has a cavity width orreceiving dimension W4. Channel walls are provided on opposite sides ofcavity 166 that have a thickness that is similar to the width dimensionof the framing (i.e., the mounting flange) portion 126 of device surface122 (see FIG. 3). The cavity width dimension W4, in at least someembodiments, is similar to the width dimension W2 of the primary heatgenerating portion or segment 124 of the package dissipating surface122.

Cavity length dimension L4, in some embodiments, is substantiallysimilar to a dimension formed by the oppositely facing edges of thedissipating surfaces of the device packages at the ends of the devicerow attached to the sink member. This dimension will be slightly smallerthan the combined lengths (e.g., L3) of the device packages 90, 92, 94and 96 in most cases. When cavity 160 is so dimensioned, a relativelysmall sink assembly is constructed which still provides effectivecooling to devices attached thereto.

Referring still to FIGS. 3 and 6, within cavity 166, body member 160includes three separate cavity dividing members including a central orfirst dividing member 180 and second and third lateral dividing memberscollectively identified by numeral 182. As its label implies, centraldividing member 180 is positioned centrally within cavity 166 andgenerally divides the cavity into two separate channels. Centraldividing member 180, in the illustrated embodiment, extends such thatits distal end is flush with surface 164 of body member 160. Inaddition, central dividing member 180 extends all the way to a first end184 of cavity 166 but stops short of a second end 186 of the cavity, thesecond end 186 being opposite first end 184.

Each of the second and third dividing members 182 is positioned on adifferent side of central member 180 and each stops short of both thefirst cavity end 184 and the second cavity end 186. In addition, each ofdividing members 182 forms a plurality of openings so that liquidflowing on either side of the member can pass to the opposite side ofthe member. Exemplary openings are identified by numeral 190 in FIG. 3.Like central member 180, in the illustrated embodiment, each of thesecond and third lateral members 182 extends such that its distal end isflush with surface 164 of body member 160.

With openings 190 formed in each of dividing members 182, what remainsof members 182 includes protuberances 290 that essentially break up theflow of coolant through the two channels formed within the cavity 166 asdescribed in greater detail below. In the illustrated embodiment theprotuberances 290 are essentially equi-spaced along the channel lengths.

At the first end 144 of the sink member, in the illustrated embodiment,body member 160 forms an inlet or receiving chamber 192 and first andsecond nozzle passageways 194 and 196, respectively. Inlet chamber 192is formed between end 144 and cavity 166 and is connected to cavity 166on one side of central member 180 by first nozzle passageway 194 and isconnected to cavity 166 on the other side of central dividing member 180by second nozzle passageway 196. Inlet chamber 192 has a relativelylarge cross-sectional area when compared to either of nozzle passageways194 and 196 so that inlet chamber 192 can act as a reservoir forproviding liquid under pressure to cavity 166 through the nozzlepassageways 194 and 196. In the illustrated embodiment, each of thesecond and third lateral dividing members 182 is positioned such thatthe protuberance 290 closest to the inlet nozzle passageway 194 or 196is aligned therewith. At second end 146 of body member 160, body member160 forms a channel extension 210 having a width dimension that is lessthan the cavity width W4.

Body member 160 can be formed in any manner known in the art. One methodfor providing member 160 includes providing the member without cavity166 and scraping metal out of surface 164 to provide a suitable cavity.Another method may be to form body member 160 in a mold. Othermanufacturing processes are contemplated.

Cover member 162 is a substantially planar and rigid rectilinear memberhaving a shape which mirrors the shape of surface 164. Member 162 formsan inlet opening 200 at a first end 204 and an outlet opening 202 at asecond 206. The inlet 200 and outlet 202 are formed such that, whencover member 162 is secured to surface 164, inlet 200 opens into inletchannel 192 and outlet 202 opens into extension 210.

To secure cover member 162 in a hermetically sealed manner to surface164, any method known in the industry can be employed. One method whichhas been shown to be particularly useful in providing a hermetic sealbetween cover member 162 and body member 160 has been to use a vacuumbrazing technique where a bead of brazing material is provided alongsurface 164 of body member 160, cover member 162 is provided on surface164 with the brazing bead sandwiched between members 162 and 160 andthen the component assembly is subjected to extremely high heat therebycausing a brazing function to occur. Other securing methods arecontemplated.

As illustrated, each of body member 160 and cover member 162 form aplurality of apertures (not separately numbered) for receivingmechanical components such as screws, bolts, etc., for mounting devicepackages 90, 92, 94 and 96 and, perhaps, other electronic devices, tothe sink member 102. In addition, body member 160 and/or cover member162 may include other apertures for mounting other converter components(e.g., the bracket described below) to sink member 102 and/or to mountthe sink member 102 within a converter housing for support.

Referring once again to FIG. 2 and also to FIG. 5, capacitors 50 arestandard types of capacitors and, to that end, generally include acylindrical body member having a first end 220 and a second end 222opposite the first end 220 where terminals 224 and 226 extend from eachfirst end 220 and a heat conducting extension 228 (see FIG. 5) extendscentrally from each second end 222. The heat conducting extensions 228,as the label implies, conducts most of the heat from the central core ofthe capacitor. Each capacitor 50 has a length dimension L1 whichseparates the first and second ends 220 and 222.

Referring now to FIGS. 2, 4 and 5, bracket member 104 is, in at leastone embodiment, formed of a heat conducting, rigid material such asaluminum or copper. Bracket member 104 includes a proximal member 230,an intermediate member 232 and a distal member 234. Proximal member 230includes a flat elongated member which has a length substantially equalto the length of sink member 102. Proximal member 230 forms a pluralityof mounting apertures along its length which align with similarapertures (not illustrated) in the surface 142 formed by cover member162 (see again FIG. 3).

Intermediate member 232 forms a 90° angle with proximal member 230 andextends from one of the long edges of member 230. Similarly, distalmember 234 extends from the long edge of intermediate member 232opposite the edge linked to proximal member 230 and forms a 90° anglewith intermediate member 232. The 90° angle formed between intermediatemember 232 and distal member 234 is in the direction opposite the angleformed between proximal member 230 and intermediate member 232 so thatdistal member 234 extends, generally, in a direction opposite thedirection in which proximal member 230 extends. Although notillustrated, distal member 234 forms a plurality of apertures throughwhich the heat dissipating capacitor extension members 228 extend formounting the capacitors 50 thereto. In the illustrated embodiment,distal member 234 forms two rows of substantially equi-spaced aperturesfor receiving the capacitors 50 and arranging the capacitors 50 in twoseparate rows.

Referring again to FIGS. 2, 4 and 5, laminated bus bar 106 includes asubstantially planar member having a general shape similar to the shapeof distal member 134. Although not illustrated, it should be appreciatedby one of ordinary skill in the art that laminated bus bar 106 includesseveral metallic conducting layers where adjacent layers are separatedby insulating layers and wherein different ones of a conducting layersare linked to connecting terminals along one edge of the bus bar.Exemplary connecting terminals are identified by numeral 240 in FIGS. 2and 4.

In addition, although not illustrated, separate vias are provided in anunderside of bus bar 106 which facilitate connection of particularpoints and particular conducting laminations within bar 106 to thecapacitors juxtaposed thereunder when the converter assembly isconfigured. More specifically, referring to FIGS. 1a and 1 b once again,bus bar 106 links various emitters and collectors of the switchingdevices 30-41 and 61-72 to the positive and negative DC buses separatedby the capacitors 50 as illustrated. Thus, for example, bus bar 106links the collector of switch 30 to the positive DC bus 18, the emitterof switch 36 to the negative DC bus, the collector of switch 31 to thepositive DC bus 18, the emitter of switch 37 to the negative DC bus 20,and so on.

It should be appreciated that bus bar 106 can have an extremely simpleand hence minimally expensive construction when used with a sink andswitching device configuration that aligns all intra-converterconnection terminals in a single line and in a single connection plane.Here only a minimal number of laminate layers are required and no viasare required to link to the switching devices as connection terminals240 are within the same plane as the device terminals.

With the converter components configured as described above, aparticularly advantageous converter assembly can be assembled asfollows. First, after the cover member 62 has been hermetically sealedto body member 160, device packages 90, 92, 94 and 96 are mounted tomounting surface 140 of sink member 102 so as to form a single devicerow as illustrated best in FIG. 4. Next, bracket member 104 is securedto surface 142 of cover member 102 so that intermediate member 232generally extends away from sink member 102 and so that distal member234 also extends generally away from sink member 102. Capacitors 50 arenext mounted to distal member 234 with their extending heat dissipatingextensions 228 passing through apertures in member 234 and so that thecapacitors 50 form two capacitive rows as illustrated in FIGS. 2 and 5.

At this point, it should be appreciated that, when bracket member 104 issuitably dimensioned, the connection terminals 224 and 226 that extendfrom the first ends 220 of the capacitors 50 should be within the sameconnection plane as the intra-converter connection terminals extendingtoward the capacitors 50 from each of device packages 90, 92, 94 and 96.To this end, the bracket member 232 should be chosen such that thelength dimension L2 of intermediate member 232, when added to the sinkmember thickness T3 and the device thickness T1 (not illustrated),essentially equals the capacitor length L1. When any of the sink member102, the capacitors 50 or the device packages (e.g., 90) are replaced byother components having different dimensions, the differentlydimensioned components can be accommodated and the capacitor and devicepackage connecting terminals can be kept within the same plane byselecting a bracket member 104 having a different intermediate member232 length dimension L2. Thus, the bracket-sink member assembly rendersthe sink member extremely versatile when compared to previous sinkconfigurations that required multi-plane serpentine coolant paths.

With the capacitor connecting terminals and the intra-converterterminals extending from the device packages within the same connectionplane, planar and relatively simple bus bar 106 is attached to thecapacitor and intra-converter terminals thereby linking the variousterminals to the positive and negative buses 18 and 20 in the fashionillustrated in FIGS. 1a and 1 b above.

Continuing, the input and output bus bars 12′, 14′, 16′, 24′, 26′ and28′ are next linked to the inter-converter connection terminals asillustrated in FIG. 4 and to link the emitters and capacitors of theswitching devices 30-41 and 61-72 at the common nodes (e.g., 46, 80,etc.) as illustrated in FIGS. 1a and 1 b.

Referring now to FIG. 5, when all of the components described above aresecured together in the manner taught, an extremely compact converterassembly that requires a relatively small volume is configured. In fact,as illustrated, a space 280 is formed adjacent surface 142 of covermember 162 and adjacent intermediate member 232 where additionalcomponents such as the components required to configure controller 22can be mounted. In some embodiments, at least some of the components ofcontroller 22 will be mounted within cooling space 280 to a secondmounting surface formed by surface 142 of cover member 162 so that themounted components dissipate heat into sink member 102.

Referring again to FIGS. 3 and 6, with cover member 162 secured tosurface 164, when liquid is pumped through inlet 200 and into inletchamber 192, after chamber 192 fills with liquid, the liquid is forcedthrough each of restricted nozzle inlets 194 and 196 into opposite sidesof cavity 166 (i.e., into different halves of cavity 166 where thehalves are separated by central dividing member 180). Because the nozzlepassageways 194 and 196 are restricted, the coolant is forcedtherethrough under pressure which should overcome any pressuredifferential that exists within the opposite sides of cavity 166. As theliquid passes through cavity 166 on its way to and out outlet 202, theliquid heats up between first channel end 184 and second channel end 186and a phase change occurs wherein at least a portion of the liquid, asheat is absorbed, changes from the liquid state the state gas therebyforming bubbles within cavity 166.

Protuberances 290 cause excessive amounts of turbulence within cavity166 as the protuberances 290 redirect liquid along random trajectorieswithin the channels. The excessive turbulence within cavity 166 is suchthat essentially no gas pockets form on the internal surfaces of thecavity 166 or the portion of cover member 162 enclosing cavity 166. Inembodiments where sink member 102 is vertically aligned, bubbles thatform within the cavity float upward under the force of liquid flow andthe force of their own buoyancy. The bubbles proceed out the outlet 202and are thereafter condensed by the cooling system attached thereto asthe refrigerant is cooled.

In FIG. 6, as indicated above, cavity 166 has a width dimension W4 thatis, at least in one embodiment, similar to the width dimension W2 of theheat generating portion of device or package surface 122 (see also FIG.3). Where dimension W2 is smaller, it is contemplated that the dualchannel aspect of cavity 166 may not be required. For example, assumedimension W2 is half the dimension illustrated in the figures. In thiscase, the cavity 166 may be made approximately half the illustrateddimension and hence central member 180 may not be needed.

Experiments have shown that if width dimension W4 is too large and nodividers 180 are provided along the cavity length L4, the turbulencegenerated by the protuberances 290 is substantially reduced. Thus, forinstance, assume member 180 were removed from cavity 166. In this casemuch of the coolant pumped into cavity 166 through passageways 194 and196 would pass relatively calmly through to the outlet end 186 of cavity166. The maximum width of each channel formed within cavity 166 is goingto be a function of various factors including cavity depth, coolantemployed, coolant pressure, the quantum of heat generated by devicepackages mounted to the sink, etc.

It should be appreciated that the protuberances 290 and divider 180within cavity 166 are specifically provided to increase channelturbulence to a level that eliminates gas pockets on channel surfaces.Without gas pockets on the channel surfaces, refrigerant/coolant is insubstantially full contact with all channel surfaces and the temperaturedifferential between the first and second channel ends 184 and 186 issubstantially reduced. The smaller channel temperature differentialmeans that devices mounted to sink member 102 have more similaroperating characteristics as desired.

Referring now to FIG. 9 a method 300 according to one aspect of thepresent invention is illustrated. Here, at block 302, a body member 160(see again FIG. 3) having a limited width dimension W3 and a length L5is provided where the limited width dimension is substantially similarto or identical to the width dimension W1 of the devices to be attachedthereto. At block 304, a cavity is formed in a first surface of the bodymember 160 that extends substantially along the entire length dimensionL5. The cavity is illustrated as 166 in FIG. 3. At block 306, a covermember 162 is provided that is consistent with the teachings above. Atblock 308 an inlet is formed in one of the body member and the covermember. At block 310 an outlet is formed in one of the body member andthe cover member. As above, the inlet and outlet formed should open intoopposite ends of the cavity or channel 166. At block 312, the covermember 162 is hermetically sealed in any manner known in the art to thebody member 160 thereby providing an enclosed channel having only asingle inlet and a single outlet at opposite ends. Continuing, at block314, power switching devices for packages 90, 92, 94 and 96 are mountedto the second or mounting surface with their dissipating widthdimensions substantially parallel to the receiving width dimension W3 ofthe heat sink.

While the system described above includes four separate power switchingdevice modules, two modules configured to provided a rectifier and twomodules configured to provide an inverter, it should be appreciated thatother applications may require more or less power capability. Where lesspower is required, if suitable, only two power switching device modulesmay be required. In this case, the heat sink member 102 may be maderelatively shorter so as to, generally, accommodate the two modules.Where more power capability is required, in at least some applications,because a temperature differential may occur if an excessive number ofmodules are aligned along a relatively long length heat sink member, ifwill be desirable to provide more than one heat sink member like member102. In this case, two or more sink members may be aligned essentiallyend to end with the switching device modules on each of the membersaligned in a single line or, in the alternative, two sink members may bevertically aligned so as to be substantially parallel to each other. Ineither of these two cases, a single bracket member and a singlelaminated bus bar may be configured to link all of the module switchingdevices and capacitors together thereby forming a suitable convertertopology.

Referring now to FIGS. 10a, 10 b and 10 c, a relatively high powerembodiment of the present invention will be described in the context ofan exemplary motor control system 348 including a rectifier assemblygenerally illustrated in FIG. 10a which feeds a capacitor bank in FIG.10b and an inverter assembly generally illustrated in FIG. 10c whereeach of the rectifier and inverter are controlled by a controller 350.As known in the controls industry, the rectifier (FIG. 10a) receivesthree-phase AC voltage on input lines 352, 354, and 356 and convertsthat three-phase voltage to a DC potential across positive and negativeDC buses 360 and 362, respectively. The DC buses 360 and 362 generallyfeed the capacitive bank (FIG. 10b) and the inverter configuration (seeagain FIG. 10c) which converts the DC potential to three-phase ACvoltage waveforms that are provided to a three-phase load via first,second and third inverter output lines 468, 470 and 472, respectively.

The rectifier assembly in FIG. 10a includes first through fourthseparate power switching device modules 368, 370, 372 and 374 where eachof the switching device modules includes six separate power switchingdevices. For example, module 368 includes switching devices 376-381,module 370 includes switching devices 382-387 and so on. First andsecond switching devices in module 372 are identified by numerals 388and 390 and first and second switching devices in module 374 areidentified by numerals 391 and 392, respectively. The switching devicesare arranged between the positive and negative DC buses 360 and 362,respectively, to provide 12 separate rectifier legs. Each rectifier legincludes a pair of series connected switching devices that traverse thedistance between the positive and negative DC buses 360 and 362,respectively. For example, a first rectifier leg includes an upperswitch 376 and a lower switch 377 that are in series between positivebus 360 and negative bus 362, a second rectifier leg includes an upperswitch 378 and a lower switch 379 that are in series between buses 360and 362, and so on. Each power switching device module 368, 370, 372 and374 includes first, second and third rectifier legs or switch pairs.Hereinafter, the labels first, second and third switch pairs will beused to refer the left most, center and right most switch pairs on eachof modules 368, 370, 372 and 374. For example, referring still to FIG.10a, switches 376 and 377 will be referred to as the first switch pairof module 368, switches 378 and 379 will be referred to as the secondswitch pair of module 368 and switches 380 and 381 will be referred toas the third switch pair of module 368. Similarly, switch pairs 382 and383, 384 and 385 and 386 and 387 will be referred to as the first,second and third switch pairs of module 370, and so on.

The nodes between switches in each device pair are referred to as commonnodes (i.e., a node that is common to the switch pair). A common nodebetween switches 376 and 377 is identified by numeral 400, a common nodebetween switches 378 and 379 is identified by numeral 408 and the commonnode between switches 380 and 381 is identified by numeral 401. Thecommon nodes for the first, second and third switch pairs in module 370are identified by numerals 402, 410 and 403, respectively, the commonnodes for the first, second and third switch pairs in module 372 areidentified by numerals 404, 412 and 405 and the common nodes for thefirst, second and third switch pairs in module 374 are identified bynumerals 406, 414 and 407, respectively.

Each of input lines 352, 354, and 356 is separately linked to fourdifferent common nodes where each node is from a different one of themodules and no common node is linked to more than one input line. Forexample, as illustrated, line 352 is linked to common nodes 400, 402,404 and 406. In a similar fashion, input line 354 is linked to commonnodes 408, 410, 412 and 414 while input line 356 is linked to commonnodes 401, 403, 405 and 407. As described above with respect to FIGS. 1aand 1 b, switch emitters, collectors and gates are identified via E, Cand G labels, respectively, in FIG. 10a (as well as in FIG. 10cdescribed below).

Control bus 358, which represents a plurality of different controllines, links controller 350 separately to each one of the rectifierswitches for independent control. Controller 350 controls when each ofthe switches turns on and when each of the switches turns off. Switchpairs having their common nodes linked to the same input line arecontrolled in identical fashion by controller 350.

Referring to FIG. 10b, the rectifier configuration also includes firstand second sets or pluralities of capacitors 661, 663 linked between thepositive and negative DC buses 360 and 362. More specifically, thecapacitors include a first upper set 661 linked between positive DC bus360 and a neutral bus 361 and a second lower set 663 linked betweennegative DC bus 362 and neutral bus 361.

Referring now to FIG. 10c, the inverter configuration illustrated, likethe rectifier configuration of FIG. 10a, includes first through fourthseparate power switching device modules 420, 422, 424, and 426 (also,sometimes referred to fifth through eighth modules, respectively) whereeach module includes six separate power switching devices arranged infirst, second and third device pairs between the positive and negativeDC buses 360 and 362, respectively. For example, module 420 includes afirst switch pair including an upper switch 428 and a lower switch 429arranged between buses 360 and 362, a second switch pair includes anupper switch 430 and a lower switch 431 and a third switch pair includesswitches 432 and a lower switch 433. The switches that comprise thefirst switch pair in module 422 are separately identified by numerals434 and 435, the switches that comprise the first switch pair in module424 are separately identified by numerals 440 and 441 while the switchesthat comprise the first switch pair of module 426 are identified bynumeral 446 and 447. As in the case of the rectifier configuration,hereinafter, unless indicated otherwise, the left most, center and rightmost switch pairs in each of modules 420, 422, 424 and 426 asillustrated in FIG. 10c will be referred to as the first, second andthird switch pairs of the respective modules.

In FIG. 10c, the common nodes corresponding to the first switch pairs ofeach of modules 420, 422, 424, and 426 are identified by numerals 450,452, 454 and 456. Similarly, the common nodes corresponding to thesecond switch pairs in each of the modules 420, 422, 424, and 426 areidentified by numerals 458, 460, 462 and 464 while the common nodescorresponding to the third switch pairs in each of the modules 420, 422,424, and 426 are identified by numerals 471, 473, 475 and 477.

In the illustrated embodiment, each output line 468, 470 and 472 islinked to four separate common nodes from different modules. Forexample, output line 472 is linked to each first switch pair common nodeincluding nodes 450, 452, 454 and 456. Similarly, output line 470 islinked to each second switch pair common node including nodes 458, 460,462 and 464 while line 468 is linked to each third switch pair commonnode 471, 473, 475 and 477.

Control bus 358 from controller 350 is linked to each of the inverterswitches to independently control the turn on and turn off of thoseswitches. As in the case of the rectifier switches illustrated in FIG.10a, controller 350 controls the switches of the inverter configurationthat have common nodes linked to the same output line in identicalfashions.

Referring now to FIG. 11, an exploded perspective view of an exemplaryrectifier/inverter configuration 500 that implements the design of FIGS.10a-10 c is illustrated. Configuration 500 includes first and secondheat sink member 502 and 503, the eight power switching device modules368, 370, 372, 374, 420, 422, 424 and 426 briefly described above, abracket member 514, a plurality of capacitors collectively identified bynumeral 516, a laminated bus bar 517 and a plurality of input and outputbus bars identified by numerals 352, 354, 356, 468, 470 and 472.

Each of modules 368, 370, 372, 374, 420, 422, 424 and 426 is similarlyconstructed and, generally, is constructed in a manner similar to theswitch packet 90 described above. Thus, each of the modules has a lengthdimension, a width dimension and a thickness dimension (see again FIGS.3 and 5) and also has first and second linking edges that face inopposite directions. As in the case of package or module 90, each of themodules in FIG. 11 includes six switching devices arranged in a singlerow relationship where first and second sub-sets of switching deviceemitters and collectors extend from opposites sides of the module andare generally separated by the device width. As above, each of themodules in FIG. 11 is designed so that all the emitter and collectorterminals extend from the module housing within a single connectionplane.

Switching device connection terminals that are linked to any of bus bars352, 354, 356, 468, 477 or 472 are referred to as inter-converterterminals because after configuration 500 is assembled, those terminalsare connected through their respective bus bars to components outsidethe converter configuration. Similarly, any device package terminalslinked to laminated bus bar 517 after configuration 500 is assembled arereferred to herein as intra-converter terminals as those terminals arelinked to other components within the converter assembly.

Referring still to FIG. 11, after exemplary configuration 500 isassembled, all of the inter-converter terminals of each module mountedto sink member 502 extend in the same direction and from a line tofacilitate easy linkage to bus bars and all of the intra-converterconnection terminals of each module mounted to sink member 502 extend inthe opposite direction and from a line to facilitate easy linkage to busbar 517 linking tabs. Similarly, after assembly, the inter-converter andintra-converter connection terminals of modules mounted to sink member503 extend in opposite directions and form inter-converter andintra-converter connection terminal lines to facilitate easy linking toassociated bus bars and the bus bar 517 linking tabs, respectively.

Referring still to FIG. 11 and also to FIG. 13, in at lease someembodiments of the present invention, configuration 500 components arejuxtaposed such that the intra-converter terminals of the modulesmounted to first sink member 502 face the intra-converter terminals thatextend from the modules mounted to second sink member 503 while theinter-converter connection terminals of the modules mounted to firstsink member 502 extend in an opposite direction from the inter-converterconnection terminals of modules mounted to second heat sink member 503.This limitation makes possible a converter configuration where a singleand relatively simple laminated bus bar can be used to link theintra-converter terminals as illustrated in FIGS. 10a, 10 c, 11, 12 and13.

Control ports (see 701 in FIG. 13) are provided on a top surface of eachpower switching device module, (e.g., 368, 370, etc.) to facilitatelinking of control bus 358 to the devices provided within the modules.Modules 368, 370, 372, 374, 420, 422, 424, and 426 are mechanicallymounted to mounting surfaces of heat sink members 502 and 503 in themanner described above with respect to FIGS. 2 and 3 (e.g., via bolts orthe like received in mounting apertures) and therefore will not bedescribed again here in detail.

Referring still to FIG. 11, consistent with the linkage patternillustrated in FIG. 10a, each of the input bus bars 352, 354 and 356 isa steel bar that has a shape such that the bar is connectable to aseparate switching device pair in each of rectifier modules 368, 370,372 and 374. More specifically, bus bar 352 includes an elongated spinemember 413 and four separate rib members that extend therefrom, aseparate rib member corresponding to each of rectifier modules 368, 370,372 and 374. In FIG. 11, the rib members linked to spine member 413 havebeen labeled with numbers corresponding to the common nodes of the firstswitching device pairs of each of the rectifier modules in FIG. 10a tohighlight the linking relationship between the ribs and thecorresponding common nodes. For example, the first rib extending fromspine member 413 in FIG. 11 that links to common node 400 in FIG. 10a issimilarly identified by numeral 400, the second rib extending from spinemember 413 that links to common node 402 in FIG. 10a is similarlyidentified by numeral 402 and the third and fourth extending ribs thatlink to common nodes 404 and 406 in FIG. 10a are similarly labeled 404and 406, respectively. A linking tab 591 extends from spine member 413generally in a direction opposite the direction of ribs 400, 402, 404and 406.

Second input bus bar 354, like first bar 352, includes a spine member411 and first through fourth rib members 408, 410, 412 an 414,respectively, that extend to one side thereof and that are juxtaposedsuch that, upon assembly, they align with and are linkable to commonnodes 408, 410, 412 and 414 of the second switch pairs of each ofmodules 368, 370, 372 and 374 as illustrated. A linking extension member593 extends in a direction opposite the ribs from spine member 411.

Third input bus bar 356 includes a spine member 409 and four rib members401, 403, 405 and 407 that extend to one side thereof and that arejuxtaposed such that, upon assembly, they align with and are linkable tosimilarly numbered common nodes 401, 403, 405 and 407 in FIG. 10a thatcorrespond to the third switching device pairs of each of modules 368,370, 372 and 374. An input linking extension 595 extends from spinemember 409 in a direction opposite the rib members.

Referring still to FIG. 11 and also to FIG. 10c, like input bus bars352, 354 and 356, output bus bars 468, 470 and 472 each include a spine,four rib members and an oppositely extending extension member forlinking to an associated output line. More specifically, bus bar 472includes spine member 540, first through fourth rib members 450, 452,454, and 456 that extend in the same direction from, and that are spacedalong spine member 540, and extension member 610 that extends in adirection opposite the rib members from spine member 540. Bus bar 470includes spine member 479, four spaced apart and similarly directed ribmembers 458, 460, 462 and 464 and extension member 612 and bus bar 468includes spine member 481, four rib members 471, 473, 475 and 477 and anoppositely extending extension member 614. Rib members 450, 452, 454 and456 are juxtaposed and spaced apart such that, upon assembly, the ribmembers align with, and are linkable to, the common nodes of each firstswitch pair in modules 420, 422, 424, and 426, respectively. Tohighlight the linkage pattern, rib members 450, 452, 454, 456 areidentified by the same numbers as the nodes to which they are linked inFIG. 10c. Similarly, rib members 458, 460, 462, 464, 471, 473, 475 and477 are juxtaposed and spaced apart such that, upon assembly, the ribmembers align with, and are linkable to, similarly numbered common nodesin FIG. 10c.

Referring again to FIG. 11 and also, again, to FIGS. 3 and 4, each ofheat sink members 502 and 503 is similar to heat sink member 102described in detail above and therefore, in the interest of simplifyingthis explanation, will not be described here in detail. However, somesimple description of members 502 and 503 will be helpful in explainingrelative juxtapositions of assembly 500 components. To this end, sinkmember 502 includes a mounting surface 530, first and second lateralsurfaces 534 and 532, respectively, and first and second lateral edges538 and 536, respectively. Edge 538 is formed by surfaces 530 and 534while edge 536 is formed by surfaces 530 and 532. Similarly, member 503includes a mounting surface 531, first and second lateral surfaces 535and 533 and first and second lateral edges 539 and 537. First lateraledge 539 is formed by the intersection of surfaces 531 and 535 whilesecond lateral edge 537 is formed by intersection of surface 531 withsurface 533.

Referring now to FIGS. 11, 12 and 13, bracket member 514 is, in theillustrated embodiment, formed of a heat conducting rigid material suchas aluminum or copper. Member 514 includes first and second proximal orlateral end members 620 and 628, two intermediate members 622 and 626and a central member 624. Each of first and second end members 620 and626 includes a flat elongated member which has a length substantiallyequal to the length of one of heat sink members 502 or 503. Each ofmembers 620 and 628 forms a plurality of mounting apertures along itslength which align with similar apertures (not illustrated) in surfacesof sink members 502 and 502 opposite mounting surfaces 530 and 531,respectively.

Intermediate members 622 and 626 form 900 angles with end members 620and 628, respectively, and extend from one of the long edges of thecorresponding end members 620 and 628. Central member 624 forms abracket mounting surface 630 that is, in the illustrated embodiment,parallel to members 620 and 628 and forms a plurality of apertures (notillustrated) for receiving heat dissipating extension members of each ofcapacitors 516. In the illustrated embodiment, central member 624 formsfour rows of substantially equispaced apertures for receiving capacitors516 and arranging the capacitors 516 in two separate rows.

Referring still to FIGS. 11, 12 and 13, laminated bus bar 517 includes asubstantially planar member having a shape similar to the shape ofcentral member 624. Referring also to FIG. 17, laminated bar 517includes several metallic conducting layers where adjacent layers areseparated by insulating layers. In FIG. 17, laminated bar 517 includesfour insulating layers (left to right downward cross hatched) 686, 687,690 and 681, a positive DC bus layer 360, a negative DC bus layer 362and a neutral bus layer 361. Also shown in FIG. 17 are positive andnegative vias and extension terminals 455 and 457 described in greaterdetail below. Positive bus 360 is insulated between layers 686 and 688,negative bus 362 is insulated between layers 688 and 690 and neutral bus361 is insulated by layers 690 and 681. Hereafter, insulating layers 681and 686 will be referred to as first and second external layers,respectively, that form first and second external surfaces 703 and 705,respectively, that face in opposite directions.

Separate insulated via's (e.g., see 707) are provided in an underside ofbus bar 517 (e.g., through insulating layer 681) which facilitateconnection of particular conducting laminations within bus bar 517 tocapacitor connection terminals juxtaposed thereunder when the converterconfiguration is assembled.

Referring again to FIGS. 10a and 10 c, bus bar 517 links variousemitters and collectors of the switching devices in the power switchingdevice modules (e.g., 368, 420, etc.) to the positive and negative DCbuses 360 and 362, respectively. For instance, laminated bar 517 linksthe collector of switch 376 to positive DC bus 360, the emitter ofswitch 377 to the negative DC bus, the collector of switch 378 to thepositive DC bus, the emitter of switch 379 to the negative DC bus, andso on.

Referring again to FIGS. 11 and 13, in addition to the componentsdescribed above, laminated bar 517 also includes linking constructs,linkages or tabs 623, 634, that extend laterally from first and secondlinking edges 708 and 710, respectively. The linking edges 708 and 710are straight and, in the illustrated embodiment, are parallel andcomprise opposite edges of bar 517. Because edges 708 and 710 arestraight, the linking tabs 632, 634 form first and second linking linesalong the edges. First and second subsets of tabs 632, 634 are linked tothe positive and negative DC bus layers 360 and 362. The tabs from thefirst and second sets are arranged and juxtaposed such that, uponassembly, the tabs align with, and are linkable to, intra-converterconnection terminals on modules 368, 370, 372, 374, 420, 422, 424 and426 to link switching devices in the modules to the positive andnegative DC buses as illustrated in FIGS. 10a and 10 c. Thus, in FIGS.10a and 10 c, laminate bar 517 links all upper switching devices (i.e.,devices illustrated above associated common nodes) to positive DC bus360 and links all lower switching devices (i.e., devices illustratedbelow associated common nodes) to negative DC bus 362.

As in the embodiment described above with respect to FIGS. 2, 3 and 4,it should be appreciated that bus bar 517 has an extremely simple andhence minimally expensive construction when used with a sink andswitching device configuration that aligns all intra-converterconnection terminals in two lines and in a single connection plane wherethe intra-converter connection terminals are located on opposite sidesand on opposite edges of the laminated bar 517. Here, despite the largenumber of power switching devices and high power capabilities, only aminimal number of laminate layers are required and no via's are requiredto link the switching devices because the connection terminals are allwithin a single plane and are located at laminate edges.

It should also be appreciated that, when bracket member 514 is suitablydimensioned, the connection terminals that extend from the capacitors516 will be within the same connection plane as the intra-converterconnection terminals extending toward the capacitors 516 from each ofmodules 368, 370, 372, 374, 420, 422, 424 and 426. Here, bracket member514 should be designed such that the length dimensions of theintermediate members 622 and 626, when added to the sink memberthickness (see again T3 in FIG. 5) and the module thickness (notillustrated) is essentially equal to the capacitor length L1 (see againFIG. 5).

In at least some embodiments it is important that linking edges 708 and710 of laminated bar 517 face in opposite directions and are parallel.In this regard, as described above, to operate most efficiently, liquidcooled sink members 502 and 503 have to be positioned such that theirinternal spaces or channels are generally vertically aligned and so thatchannel inlets are below channel outlets on the same sink member. Thus,by configuring bar 517 with oppositely facing parallel linking edges 708and 710, the requirement that both sinks 502 and 503 be aligned withtheir lengths vertical can be met. Nevertheless, other configurationsare contemplated where the linking edges may include other than paralleledges.

With the capacitor connection terminals and the intra-converterterminals extending from the device modules within the same connectionplane, planar and relatively simple bus bar 517 is attached to thecapacitor and intra-converter terminals thereby linking the variousterminals to the positive and negative buses 360 and 362 in the fashionillustrated in FIGS. 10a and 10 c above.

Next, the input and output bus bars 352, 354, 356, 472, 474 and 476 arelinked to the inter-converter connection terminals as illustrated inFIGS. 11 and 13 to link the emitters and collectors of the switchingdevices at the common nodes as illustrated in FIGS. 10a and 10 c.

Once configuration 500 has been assembled, configuration 500 is mountedwithin the space provided for by a specific application such that theinlet apertures or openings into the internal spaces formed by sinkmembers 502 and 503 are below the outlets corresponding to those spaces,and generally, so that sinks 502 and 503 are substantially verticallyaligned. Thus, when cooling liquid is pumped into the inlets at thebottoms of sink members 502 and 503, the cooling liquid moves upwardwithin the internally formed channels and exits the outlets thereaboveafter absorbing sink and module heat.

Referring once again to FIGS. 10b, 11, 12, 13 and 17, according to anadditional aspect of the present invention, positive and negative DC bustabs or external linkage terminals 455 and 457, respectively, are linkedto the positive and negative DC buses 360 and 362, respectively, of thelaminated bus bar 517. As best seen in FIG. 17, first and second vias692 and 694 are formed in laminated bar 517 through second surface 705that open into or terminate at the positive and negative DC buses 360and 362, respectively. Via 692 opens through second external insulatinglayer 686 while via 694 opens through layer 686, DC bus layer 360 andinsulating layer 688. The lateral internal walls of via 694 are layeredwith an insulator 696 to avoid a short between the positive and negativeDC buses 360 and 362. Terminals 455 and 457 extend through vias 692 and694, link to positive and negative DC bus layers 360 and 362 and haveexposed distal ends linkable to either a DC source or a load requiringDC power. Terminals 455 and 457, in the illustrated embodiment, extendin a perpendicular direction from the top surface of laminated bar 512although other extending directions and configurations are contemplated.

With DC bus tabs 455 and 457 extending as illustrated, the configurationdescribed above can be linked to power sources and loads in severaldifferent ways and can be controlled by controller 350 in various waysto facilitate several types of power conversion. For example, asdescribed above, a three-phase source can be linked to input lines 352,354, and 356 and a three-phase load can be linked to output lines 468,470 and 472 and controller 350 can control modules 368, 370, 372 and 374to facilitate rectification while controlling modules 420, 424, 424 and426 to facilitate inversion to provide a three-phase AC/AC converter. Asanother example, with a three-phase AC source linked to input lines 352,354 and 356, controller 350 may control modules 368, 370, 372 and 374 torectify the AC power and provide a DC source on positive and negative DCbuses 360 and 362 and thereby to positive and negative DC terminals 455and 457. Here, a load requiring DC voltage may be linked to terminals454 and 457 to receive power therefrom. As another example, a firstthree-phase source may be provided at input lines 352, 354 and 356 whilea second three-phase source is provided at lines 468, 4670 and 472 andcontroller 350 may be used to control all of modules 368, 370, 372, 374,420, 422, 424 and 426 to facilitate rectification thereby providing ahigher DC power at tabs 455 and 457.

In yet another example, a separate DC source that is not illustrated maybe linked to terminals 455 and 457, a first AC load may be linked tolines 352, 354 and 356, the second three-phase AC load may be linked tolines 468, 470 and 472 and controller 350 may control modules 368, 370,372 and 374 as well as modules 420, 422, 424 and 426 to provide DC/ACpower conversion. Thus, it the positive and negative DC terminals 455and 457 linked to the DC buses formed by laminated bar 517 appreciablyincrease the versatility of the relatively complex and large scaleconversion configuration illustrated in FIGS. 10a through 13.

Referring still to FIG. 11, by linking each of the input and output busbars 352, 354, 356, 468, 470 and 472 to switch pairs in each powerswitching device module (e.g., 368, 370, etc.), the disparate operatingranges of power switching devices in different modules average and theoverall conversion that occurs yields for better results.

The advantages of having input and output bus bars that are linked topower switching devices in each of a plurality of different powerswitching device modules are obtainable in any configuration where theswitches in two power switching device modules are to be controlledtogether to provide either rectification or inversion. For example,referring again to FIG. 1a and FIG. 2, input bus bars 12′, 14′ and 16′may each be shaped and configured such that input line 16 is linked tothe common nodes between switches 30 and 36, and switches 33 and 39,line 14 is linked to the common nodes switches 31 and 37 and switches 34and 40 and line 12 is linked to the common nodes between switches 32 and38 and switches 35 and 41, assuming switching devices 30, 31, 32, 36, 37and 38 are on a first power switching device module and devices 33, 34,35, 39, 40 and 41 are on a second power switching device module. Similarcomments are applicable to the inverter configuration illustrated inFIG. 1b where each of lines 24, 26 and 28 may be linked to first andsecond common nodes where the first and second common nodes correspondto switch pairs on different device modules.

Other bus bar configurations, in addition to those illustrated in FIGS.11-13 above, are contemplated that provide similar multi-modular switchaveraging results. To this end, the components illustrated in FIG. 10ahave been re-illustrated in FIG. 14, the only difference being thelinking pattern between input lines 352, 354 and 356 and the switch paircommon nodes. Specifically, comparing FIGS. 10a and 14, where a nodelinkage appearing in FIG. 10a has been altered in FIG. 14, the alteredlinkage in FIG. 14 is identified by the same number used to label thelinkage in FIG. 10a followed by a “′”. For example, common node 402 inFIG. 10a, which is linked to input line 352 has been replaced in FIG. 14by similarly numbered common node 402′ (e.g., the common node of thethird switch pair including switches 386 and 387 in module 370).Similarly, common node 406 linked to line 352 in FIG. 10a has beenreplaced in FIG. 14 by similarly numbered common node 406′, the commonnode formed by the second switch pair in module 374.

In FIG. 14, first input line 352 is linked to common node 400corresponding to the first switching device pair in module 368, thecommon node 402′ corresponding to the third switching device pair inmodule 370, the common node 404 corresponding to the first switchingdevice pair in module 372 and common node 406′ corresponding to thesecond switching device pair in module 374. In addition, line 354 islinked to the common node 408 corresponding to the second switchingdevice pair in module 368, the common node 410 corresponding to thesecond switching device pair in module 370, the common node 412′corresponding to the third switching device pair in module 372 and thecommon node 414′ corresponding to the first switching device pair inmodule 374. In addition, third input line 356 is linked to the commonnode 401 corresponding to the third switching device pair in module 368,common node 403′ corresponding to the first switching device pair inmodule 370, common node 405′ corresponding to the second switchingdevice pair in module 372 and common node 407 corresponding to the thirdswitching device pair in module 374.

As illustrated in FIG. 14, each of the lines 352, 354 and 356 is linkedto at least two adjacent common nodes where the adjacent common nodesare in different power switching devices modules. For example, line 352is linked to common node 402′ in module 370 and is also linked toadjacent common node 404′ in module 372. Similarly, line 354 is linkedto common node 412′ in module 372 and also to adjacent common node 414′in module 374 while line 356 is linked to common node 401 in module 368and to common node 403′ in module 370.

Referring now to FIG. 15 and also to FIG. 11, modules 368, 370, 372 and374 are re-illustrated in FIG. 15 and a second embodiment of bus barsfor linking to switching modules as shown in FIG. 14 is illustrated.Like bars 352, 354 and 356 in FIG. 11, bars 652, 654, 656 each include aspine member 409, 411 and 413, respectively, and a plurality of ribmembers which extend in the same direction therefrom. However, insteadof including four rib members, each of bars 352, 354 and 356 includesonly three rib members. For example, bar 352 includes a first rib member400, a second “double-wide” rib member identified by both numerals 402′and 404 and a third rib members identified by number 406′.

Referring still to FIG. 15, bar 654 includes first rib member 408,second rib member 410 and a third double-wide rib member identified bynumerals 412′ and 414′ while third bar 656 includes a first double-widerib member identified by numerals 401 and 403′, a second rib member 405′and a third rib members 407′. In FIG. 15, bars 652, 654, 656 arejuxtaposed with respect to modules 368, 370, 372 and 374 such that therib members of each bar are aligned with the intra-converter switchingdevice connection terminals that the bar links up with upon assembly ofan associated converter configuration. To this end, it can be seen thatrib member 400 links to connection terminals 376E and 377C, rib member408 links to connection terminals 378E and 379C, rib member 401 links toconnection terminals 380E and 381C and so on.

Each double-wide rib member links to a switching device pair in each oftwo adjacent power switching device modules to perform the function oftwo of the rib members in the embodiment illustrated in FIG. 11. Forexample, the double-wide rib member identified by numerals 402′ and 404straddles adjacent switch pairs in modules 370 and 372 to perform thelinking functions corresponding to similarly numbered common nodes 402′and 404′ in FIG. 14. Similarly, double-wide rib member identified bynumerals 412′ and 414′ straddles adjacent switching pairs in modules 372and 374 to perform the linking function associated with similarly markedcommon nodes 412′ and 414′ in FIG. 14 while the double-wide rib memberidentified by numerals 401 and 403′ straddles the switch pairs inmodules 368 and 370 thereby performing the linking functioncorresponding to common nodes 401 and 403′ in FIG. 14. Each single widerib (e.g., 400, 406, etc.) member in FIG. 15 is juxtaposed with respectto an associated double-wide rib member such that the single-wide memberlinks to a switch pair in a module other than a module to which theassociated double-wide rib member is linked. For instance, consistentwith FIG. 14, rib member 400 is juxtaposed to link to the first switchpair of module 368 while rib member 406′ is juxtaposed to link to thethird switch pair of module 374. Thus, the FIG. 15 bus bar configurationprovides a function identical to the function of the bus barsillustrated in FIG. 11 where each bus bar 652, 654 and 656 is linked tofour separate switch pairs, each linked pair from a different one ofmodules 366, 370, 372 and 376.

Referring next to FIG. 16, a third bus bar embodiment is illustratedwhich includes bus bars 660, 662 and 664 that align with modules 368-374in FIG. 15 in a different fashion but that nevertheless performfunctions identical to the bus bars illustrated in FIG. 11. Bars 660,662 and 664, each include a single spine member 409, 411 and 413,respectively. However, instead of including identical numbers of ribmembers, each of bus bars 660, 662 and 664 includes a different numberof rib members. Bus bar 660 includes first and second double-wide ribmembers 666 and 670, bar 662 includes first, second and third ribmembers 672, 674 and 676 where member 674 is double-wide and bar 664includes first through fourth single-wide rib members 678, 680, 682 and684, respectively. Rib member 666 is formed so as to straddle adjacentswitch pairs in modules 368 and 370 while rib member 670 is sized andpositioned with respect to rib member 666 such that, when rib member 666straddles the adjacent switch pairs in modules 368 and 370, rib member670 straddles adjacent switch pairs in modules 372 and 374. Second busbar rib member 674 is sized so as to straddle the connection terminalsof adjacent switch pairs in modules 370 and 372 while each of ribmembers 672 and 676 is sized and juxtaposed with respect to rib member674 such that, when rib member 674 straddles adjacent switch pairs inmodules 370 and 372, rib member 672 is linkable to one pair of switchingdevices in module 368 and rib member 676 is linkable to one pair ofswitching devices in module 374. Rib members 678, 680, 682 and 684 aresized and juxtaposed with respect to each other such that each of thoserib members links to a separate pair of switching devices in each ofmodules 368, 370, 372 and 374 that is not linked to one of the other ribmembers corresponding to either of bars 660 or 662. Thus, as in thecases of the bar configurations of FIGS. 11 and 15, each bar in FIG. 16links to a separate switch pair in each of modules 368, 370, 372 and374.

Although not illustrated, it should be appreciated that bus bars similarto the bars illustrated in FIGS. 15 and 16 may be used to replace bars468, 470 and 472 in FIG. 11 to provide an identical switch averagingfunction.

While various configurations and assemblies are described above, itshould be appreciated that the present invention also contemplates amethod of configuring a simple yet extremely power conversionconfiguration that is relatively inexpensive to manufacture. To thisend, one exemplary method 730 is illustrated in FIG. 18. Referring toboth FIGS. 11 and 18, at block 732, first and second liquid cooled heatsink members 502 and 503 are provided having mounting surfaces 530 and531, respectively, and having length dimensions (not labeled in FIG. 11)where each mounting surface includes first and second oppositely facingedges. For example, sink member 502 includes oppositely facing first andsecond edges 538 and 536, respectively, while sink member 503 includesoppositely facing first and second edges 539 and 537, respectively.Referring also to FIGS. 3 and 6, each of sink members 502 and 503 formsan internal chamber that extends from an inlet to an outlet for guidingcooling liquid during sink operation.

At block 734, mounting bracket 514 is mounted between the sink memberssuch that the sink member length dimensions are substantially parallel(e.g., first edges 538 and 539 of sink members 502 and 503 aresubstantially parallel). At block 735, capacitors 516 are mounted to themounting surface 630 of bracket 514. At block 736, first and secondpluralities of switching devices are mounted to the first and secondsink member mounting surface 502 and 503 such that their intra-converterand inter-converter connection terminals are proximate the first andsecond edges of the respective mounting surfaces. For instance,referring once again to FIG. 11, the first plurality of switches mayinclude the switches that form modules 368, 370, 372 and 374 while thesecond plurality may include the switches that comprise modules 420,422, 424 and 426.

At block 740 laminated bus bar 517 is used to link the intra-converterconnection terminals and the capacitors to the positive and negative DCbuses within the laminate bus bar to form the converter topologydesired. Next, at block 742, controller 350, a source and a load arelinked to the topology. This linking step at block 742 may compriseproviding and linking input and output bus bars as illustrated in FIG.11 and then linking the source and the load lines to the bus bars.

It should be understood that the methods and apparatuses described aboveare only exemplary and do not limit the scope of the invention, and thatvarious modifications could be made by those skilled in the art thatwould fall under the scope of the invention. For example, while the sinkmember 102 is described as being formed of two components otherconfigurations are contemplated. In addition, the protuberances 290 maytake other forms that cause a suitable amount of turbulence within thechannel. For instance, in FIG. 7 another embodiment of the body memberis illustrated. In FIG. 7 components similar to the components of FIG. 6are identified by identical numbers followed by an “a” qualifier. InFIG. 7, instead of providing substantially rectilinear protuberances asin FIG. 6, triangular protuberances 290 a are provided on either side ofmember 280. Moreover, the protuberances may be formed by any channelsurface although forming the protuberances on the surface opposite theheat generating devices (i.e., opposite the mounting surface) increasesthe total surface area proximate the heat generating device that is incontact with the coolant. Furthermore, both the cover and the bodymember may form protuberances and, in some embodiments, the cover membermay form part or all of the cavity 166.

In addition, while the protuberances 290 are illustrated as beingequi-spaced, equi-spacing is not required and, in fact, it may beadvantageous to provide protuberances that cause a greater amount ofturbulence at the outlet end of the channel than at the inlet end as thecoolant at the outlet end could be slightly warmer and hence couldgenerate more problematic vapor bubbles.

Moreover, more than one divider may be provided in a cavity. In thisregard, referring to FIG. 8, another inventive embodiment 160 b of thebody member is illustrated. In FIG. 8 components similar to componentsdescribed above are identified by the same number followed by a “b”qualifier. In FIG. 8 cavity 166 b is twice as wide as the cavity 166 inFIG. 6. Here, to ensure sufficient turbulence to eliminate stagnant gaspockets from the cavity surface, three separate divider members 271, 273and 275 are provided that equally divide cavity 166 b along its width.In addition, separate inlet passageways 251, 253, 255 and 257 areprovided that open from inlet chamber 192 c into each separate channelwithin cavity 166 b and separate lines of protuberances 261, 263, 265and 267 are formed within the separate channels. Thus, the protuberanceconcept has application in wider sink assemblies also although it isparticularly advantageous in long sink assemblies for the reasonsdescribed above.

In addition, while the sinks are described as being substantiallyvertically aligned and the channels as being parallel to the moundingsurfaces, in some embodiments the sinks may be a few degrees (e.g.,10-15) from vertical and the channels may not be completely parallel tomounting surfaces. Furthermore, referring again to FIG. 17, terminals455 and 457 may not be included in some embodiments while in otherembodiments vias 692 and 694 may provide the DC linking functionalityalone. Moreover, while embodiments are described above where switchingdevice modules configure each of an inverter sub-assembly and arectifier sub-assembly, other embodiments are contemplated where themodules may configure only a rectifier or only an inverter assembly.

In addition, other embodiments are contemplated including two or morevertically aligned liquid cooled sinks combined with a laminated bus barwhere the laminated bar links to power switching devices along onlyvertical straight bar edges. For instance, one additional embodiment isillustrated in FIG. 19 where sinks 502 and 503 with modules 368, 370,372, 374, 420, 422, 424, and 426 mounted thereto are vertically endaligned with switching devices linked to one straight vertical linkingedge of bus bar 517.

To apprise the public of the scope of this invention, the followingclaims are made:

What is claimed is:
 1. An apparatus for linking together power switchingdevices having intra-converter connection terminals to form a powerconversion assembly, the apparatus comprising: a planar bus barincluding positive and negative DC bus layers and insulating layers thatinsulate each of the DC bus layers, the bar also including at least afirst external insulating layer that forms a first external surface ofthe bar, the bar also forming at least first and second linking edges;and first and second pluralities of linkages formed along the first andsecond linking edges, respectively, each linkage linked to one of thepositive and negative DC bus layers and configured to be linkable to atleast one of the power switching device intra-converter connectionterminals.
 2. The apparatus of claim 1 wherein each of the linkages is alinking tab.
 3. The apparatus of claim 1 wherein first and second edgesof the bus bar face in opposite directions.
 4. The apparatus of claim 3wherein the bus bar is substantially rectilinear.
 5. The apparatus ofclaim 3 wherein the first and second edges are straight and wherein thefirst plurality of linkages are aligned along the first straight edgeand the second plurality of linkages are aligned along the secondstraight edge.
 6. The apparatus of claim 5 wherein the first and secondlinking edges are vertically aligned.
 7. The apparatus of claim 1further including first and second external linking vias open to thepositive and negative DC bus layers, respectively.
 8. The apparatus ofclaim 7 also for linking a plurality of capacitors to the switchingdevices wherein the external linking vias open through the fist externalinsulating layer and wherein the laminated bar further includes a secondexternal insulating layer on a side opposite the first externalinsulating layer and forms a plurality of vias opening through secondexternal insulating layer to the positive and negative DC bus layers,the capacitors linkable through the plurality of vias to the DC buslayers.
 9. The apparatus of claim 7 further including positive andnegative DC connection terminals that extend through the first andsecond vias and are linked to the positive and negative DC bus layers,distal ends of the DC connection terminals exposed and connectable to atleast one of a DC source and a DC load.
 10. The apparatus of claim 1 forlinking at least first and second bridge assemblies together with thecapacitors to form a conversion device and, wherein, each of thelinkages in the first plurality is linked to at least one of theintra-converter connection terminals of the first bridge assembly andeach of the linkages in the second plurality is linked to at least oneof the intra-converter connection terminals of the second bridgeassembly.
 11. A three phase electronic converter assembly comprising: atleast a first heat sink member having a mounting surface; first andsecond X phase converter bridge assemblies, each bridge assemblyincluding a plurality of power switching devices, the first bridgeassembly forming first through Xth external linkage terminals and thesecond bridge assembly forming (X+1)th through 2Xth external linkageterminals, each linkage terminal linkable to one phase of at least oneof an X phase source and an X phase load, the switching devices mountedto the mounting surface of the at least first sink member; a pluralityof capacitors; and a bus bar including a positive DC bus, a negative DCbus and a plurality of insulating layers that insulate the positive andnegative DC buses and form an external insulating layer, the capacitorsand each of the bridge assemblies linked to the positive and negative DCbuses, the bar forming first and second external linking vias that opento the positive and negative DC buses, respectively.
 12. The apparatusof claim 11 further including a positive DC bus connection terminallinked to the positive DC bus and having a distal end extending throughthe first via and exposed for external connection and a negative DCconnection terminal linked to the negative DC bus and having a distalend extending through the second via and exposed for externalconnection.
 13. The apparatus of claim 12 wherein the bus bar is planarproximate the first and second vias and wherein each of the positive andnegative connection terminals extend substantially perpendicularly tothe bus bar plane proximate the vias.
 14. The apparatus of claim 13including a second sink member having a mounting surface and, wherein,the first bridge assembly is mounted to the mounting surface of thefirst sink member and the second bridge assembly is mounted to themounting surface of the second sink member.
 15. The apparatus of claim14 further including a bracket member rigidly linked to and between thefirst and second sink members, the plurality of capacitors mounted tothe bracket member substantially between the first and second sinkmembers.
 16. The apparatus of claim 15 further including a controllerfor controlling each of the first and second bridge assemblies tooperate as at least one of a rectifier and an inverter.
 17. Theapparatus of claim 15 wherein the first bridge assembly includes atleast first and second three phase converter bridges and the secondbridge assembly includes at least first and second three phase converterbridges.
 18. The apparatus of claim 11 wherein X is
 3. 19. The apparatusof claim 18 wherein the first three phase converter bridge assemblyincludes power switching devices that form at least first and secondthree phase bridges and the second three phase converter bridge assemblyincludes power switching devices that form at least first and secondthree phase bridges, each of the three phase bridges including threepairs of switching devices, each of the switching device pairs includingan upper switching device and a lower switching device, each deviceincluding intra-converter connection terminals and inter-converterconnection terminals, the linkage assembly linking the intra-converterconnection terminals of each of the upper devices to the positive DC busand linking the intra-converter connection terminals of each of thelower switching devices to the negative DC bus, the inter-converterconnection terminals forming the first through third external linkageterminals of the first bridge assembly and forming the fourth throughsixth external linkage terminals of the second bridge assembly.
 20. Theapparatus of claim 11 wherein the first bridge assembly includes atleast first and second three phase converter bridges and the secondbridge assembly includes at least first and second three phase converterbridges.
 21. The apparatus of claim 9 wherein the sink member is aliquid cooled heat sink.
 22. A three phase electronic converter assemblycomprising: a first heat sink member having a mounting surface; a secondheat sink member having a mounting surface; first and second X phaseconverter bridge assemblies, each bridge assembly including a pluralityof power switching devices, the first bridge assembly forming firstthrough Xth external linkage terminals and the second bridge assemblyforming (X+1)th through 2Xth external linkage terminals, each linkageterminal linkable to one phase of at least one of an X phase source andan X phase load, the first assembly switching devices mounted to thefirst sink member mounting surface and the second assembly switchingdevices mounted to the second sink member mounting surface; a pluralityof capacitors; a bus bar including a positive DC bus, a negative DC busand a plurality of insulating layers that insulate the positive andnegative DC buses and form an external insulating layer, the capacitorsand each of the bridge assemblies linked to the positive and negative DCbuses, the external insulating layer forming first and second vias thatopen to the positive and negative DC buses, respectively.
 23. Theapparatus of claim 22 further including a positive DC bus connectionterminal linked to the positive DC bus and having a distal end extendingthrough the first via and exposed for external connection and a negativeDC connection terminal linked to the negative DC bus and having a distalend extending through the second via and exposed for externalconnection.
 24. The apparatus of claim 23 wherein the bus bar is planarproximate the first and second vias and wherein each of the positive andnegative connection terminals extend substantially perpendicularly tothe bus bar plane proximate the vias.